Some boards or SoCs need the SRC_SCR[WARM_RESET_ENABLE] bit cleared,
otherwise they won't come up after a watchdog reset. This was observed
on one i.MX6ul based custom board. The Linux Kernel does the same since
2012: 0575fb7 ARM: 7198/1: arm/imx6: add restart support for imx6q.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>