drivers/firmware/memmap.c: modify memblock_alloc to memblock_alloc_nopanic

memblock_alloc() never returns NULL because panic never returns.

Link: http://lkml.kernel.org/r/1545640882-42009-1-git-send-email-huang.zijiang@zte.com.cnSigned-off-by: huang.zijiang <huang.zijiang@zte.com.cn>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/firmware/memmap.c

@@ -333,7 +333,7 @@ int __init firmware_map_add_early(u64 start, u64 end, const char *type)
 {
 	struct firmware_map_entry *entry;
 
-	entry = memblock_alloc(sizeof(struct firmware_map_entry),
+	entry = memblock_alloc_nopanic(sizeof(struct firmware_map_entry),
 			       SMP_CACHE_BYTES);
 	if (WARN_ON(!entry))
 		return -ENOMEM;