uboot-imx

Prevent crash if random/invalid ramdisks are passed to bootm

Adds returning an error from the ramdisk detection code if
its not a real ramdisk (invalid).  There is no reason we can't
just return back to the console if we detect an invalid
ramdisk or CRC error.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>