mm, elf: handle vm_brk error

load_elf_library doesn't handle vm_brk failure although nothing really
indicates it cannot do that because the function is allowed to fail due to
vm_mmap failures already.  This might be not a problem now but later patch
will make vm_brk killable (resp.  mmap_sem for write waiting will become
killable) and so the failure will be more probable.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>