uboot-imx

ipu common: reset ipuv3 correctly

This patch checks self-clear sw_ipu_rst bit in
SCR register of SRC controller to be cleared
after setting it to high to reset IPUv3. This
makes sure that IPUv3 finishes sofware reset.
A timeout mechanism is added to stop polling
on the bit status in case the bit could not be
cleared by the hardware automatically within
10 millisecond.

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>