i.mx6q: mx6qarm2: Enable the usboh3 clock

Bits 0 and 1 of CCM_CCGR7 are the usboh3 clock enable bits. Enabling this
clock is necessary for the USB download.

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
CC: Jason Hui <jason.hui@linaro.org>
Acked-by: Jason Hui <jason.hui@linaro.org>

board/freescale/mx6qarm2/imximage.cfg

@@ -164,4 +164,4 @@ DATA 4 0x020c4070 0x0FFFC000
 DATA 4 0x020c4074 0x3FF00000
 DATA 4 0x020c4078 0x00FFF300
 DATA 4 0x020c407c 0x0F0000C3
-DATA 4 0x020c4080 0x000003FC
+DATA 4 0x020c4080 0x000003FF