When the kernel load address is chosen by the user/image we need
to check if the kernel needs to relocate itself before decompression.
If that's the case the spacing behind the kernel must allow for this
relocation without overwriting anything placed behind the kernel.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>