GameDB: give Rogue Galaxy the asynchronous GS download mode

Rogue Galaxy blocks the GS thread 7.5 ms every frame to read back sixty-four
pixels. It is an 8x8 patch of the depth buffer at a fixed screen position, read
once a frame -- a depth occlusion probe, the test a game does before deciding
whether to draw a lens flare. The cost is entirely GPU-fence synchronisation, so
it does not scale with the payload: the emulator submits, waits for the GPU to
finish, and reads 256 bytes.

The asynchronous download mode issues the same copy into a throwaway staging
texture and retires it at a later vsync, so the GS thread never waits. Measured
on the M2 by timing the readback directly rather than the frame, which keeps the
number clear of the gsrunner -perf perturbation: 7.2-7.8 ms becomes 0.005-0.008
ms. On a 45 ms frame that stall was around a fifth of the time.

It is not the blunt option. NoReadbacks and Unsynchronized, which this overlay
already ships for other titles, either skip the readback or race it. Async does
the real download and merely serves it a frame late, and it drops a late result
outright when an EE upload or a local-to-local move has since claimed those
pages, so stale data cannot overwrite newer contents.

Output is unchanged on every frame we can compare: four captured scenes, thirty
two colour frames, all pixel-identical, each scored against three baseline runs
of the unmodified binary first so run-to-run dump nondeterminism could not be
read as a result.

What that evidence cannot cover is motion. A frame-old occlusion probe differs
from a fresh one exactly when the probe's answer changes, which needs the camera
or the light to move, and every capture we hold is near-static. The visible
failure would be a lens flare blinking a frame late as it passes behind
scenery. That is the thing to watch for in play, and reverting is a one-line
change if anyone sees it.

Seven serials, every Rogue Galaxy entry the overlay carries, including the three
Japanese ones -- SCPS-15102, SCPS-17013 and SCPS-19254 are the same game under
its Japanese title.

OutRun 2006 is the only other title of the eight we profile that reads back at
all, three times a frame for 3.3-4.2 ms, and it is deliberately not included
here. Its readbacks are small colour buffers rather than depth, and there is an
open unexplained brightness bug in that game; feeding frame-old data into what
may be an adaptive-exposure loop is not something to do before understanding it.

bin/resources-overlay/armsx2_overrides.yaml

@@ -90,6 +90,7 @@ SCAJ-20162:
     autoFlush: 0
     disablePartialInvalidation: 1
     halfPixelOffset: 2
+    hwDownloadMode: 5
     nativeScaling: 2
     recommendedBlendingLevel: 4
     roundSprite: 1
@@ -252,6 +253,7 @@ SCES-54552:
     autoFlush: 0
     disablePartialInvalidation: 1
     halfPixelOffset: 2
+    hwDownloadMode: 5
     nativeScaling: 2
     recommendedBlendingLevel: 4
     roundSprite: 1
@@ -366,6 +368,7 @@ SCPS-15102:
     autoFlush: 0
     disablePartialInvalidation: 1
     halfPixelOffset: 2
+    hwDownloadMode: 5
     nativeScaling: 2
     recommendedBlendingLevel: 4
     roundSprite: 1
@@ -377,6 +380,7 @@ SCPS-17013:
     autoFlush: 0
     disablePartialInvalidation: 1
     halfPixelOffset: 2
+    hwDownloadMode: 5
     nativeScaling: 2
     recommendedBlendingLevel: 4
     roundSprite: 1
@@ -385,6 +389,7 @@ SCPS-19254:
     autoFlush: 0
     disablePartialInvalidation: 1
     halfPixelOffset: 2
+    hwDownloadMode: 5
     nativeScaling: 2
     recommendedBlendingLevel: 4
     roundSprite: 1
@@ -592,6 +597,7 @@ SCUS-97490:
     autoFlush: 0
     disablePartialInvalidation: 1
     halfPixelOffset: 2
+    hwDownloadMode: 5
     nativeScaling: 2
     recommendedBlendingLevel: 4
     roundSprite: 1
@@ -638,6 +644,7 @@ SCUS-97572:
     autoFlush: 0
     disablePartialInvalidation: 1
     halfPixelOffset: 2
+    hwDownloadMode: 5
     nativeScaling: 2
     recommendedBlendingLevel: 4
     roundSprite: 1