The generic DT image built with CONFIG_ARCH_IMX has nothing really
i.MX specific except that it has support for i.MX features. The DT
image could be started with a non i.MX device tree which works as
expected. imx_init() panics though when started with a non i.MX device
tree. Remove the hang() so that we can just continue.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>