lpc1768: even if rclk "works", it isn't necessarily the correct clk

rclk = 4MHz oon lpc1768, the correct JTAG clk is 666MHz(4MHz/6).

Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>

tcl/target/lpc1768.cfg

@@ -50,8 +50,12 @@ flash bank $_FLASHNAME lpc2000 0x0 0x80000 0 0 $_TARGETNAME \
 # JTAG clock should be CCLK/6 (unless using adaptive clocking)
 # CCLK is 4 MHz after reset, and until board-specific code (like
 # a reset-init handler) speeds it up.
-jtag_rclk [ expr 4000 / 6 ]
-$_TARGETNAME configure -event reset-start { jtag_rclk [ expr 4000 / 6]  }
+#
+# Although rclk "appears to work", it turns out that this yields
+# 4MHz whereas the "correct" rate is CCLK/6, which is not what
+# you get with rclk.
+jtag_khz [ expr 4000 / 6 ]
+
 
 
 $_TARGETNAME configure -event reset-init {