kexec: simplify conditional

Simplify the code around one of the conditionals in the kexec_load syscall
routine.

The original code was confusing with a redundant check on KEXEC_ON_CRASH
and comments outside of the conditional block.  This change switches the
order of the conditional check, and cleans up the comments for the
conditional.  There is no functional change to the code.

Signed-off-by: Geoff Levand <geoff@infradead.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Maximilian Attems <max@stro.at>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>