ARM: 7555/1: kexec: fix segment memory addresses check

Commit c564df4d

 (ARM: 7540/1: kexec:
Check segment memory addresses) added a safety check with accidentally
reversed condition, and broke kexec functionality on ARM. Fix this.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>