Revert "drm/amdgpu/display: set vblank_disable_immediate for DC"

This reverts commit 92020e81dd.

This causes stuttering and timeouts with DMCUB for some users
so revert it until we understand why and safely enable it
to save power.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1887
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Cc: stable@vger.kernel.org

drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c

@@ -320,6 +320,7 @@ int amdgpu_irq_init(struct amdgpu_device *adev)
 	if (!amdgpu_device_has_dc_support(adev)) {
 		if (!adev->enable_virtual_display)
 			/* Disable vblank IRQs aggressively for power-saving */
+			/* XXX: can this be enabled for DC? */
 			adev_to_drm(adev)->vblank_disable_immediate = true;
 
 		r = drm_vblank_init(adev_to_drm(adev), adev->mode_info.num_crtc);

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -4259,9 +4259,6 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 		}
 	}
 
-	/* Disable vblank IRQs aggressively for power-saving. */
-	adev_to_drm(adev)->vblank_disable_immediate = true;
-
 	/* loops over all connectors on the board */
 	for (i = 0; i < link_cnt; i++) {
 		struct dc_link *link = NULL;