kexec: i386: multiboot: fix possible memory leak in multiboot_x86_load

In multiboot_x86_load, allocated memory may not be free'd if the code
exits abnormally, by calling return. So the patch fixes the possible
memory leak.

Besides, remove some extra blank lines.

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Simon Horman <horms@verge.net.au>