mtd: diskonchip: mem resource name is not optional

commit 86e4bbc7 upstream.

Passing a name to request_mem_region() isn't optional and can't just
be NULL. Passing NULL causes a NULL ptr deref later in the boot
process.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/mtd/nand/diskonchip.c

@@ -1438,7 +1438,7 @@ static int __init doc_probe(unsigned long physadr)
 	int reg, len, numchips;
 	int ret = 0;
 
-	if (!request_mem_region(physadr, DOC_IOREMAP_LEN, NULL))
+	if (!request_mem_region(physadr, DOC_IOREMAP_LEN, "DiskOnChip"))
 		return -EBUSY;
 	virtadr = ioremap(physadr, DOC_IOREMAP_LEN);
 	if (!virtadr) {