mtd: nand_bbt: refactor check_pattern_no_oob()

This function only returns 0 or -1, so make that clear.
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/nand_bbt.c

@@ -71,12 +71,9 @@
 
 static int check_pattern_no_oob(uint8_t *buf, struct nand_bbt_descr *td)
 {
-	int ret;
-
-	ret = memcmp(buf, td->pattern, td->len);
-	if (!ret)
-		return ret;
-	return -1;
+	if (memcmp(buf, td->pattern, td->len))
+		return -1;
+	return 0;
 }
 
 /**