mtd: nand_bbt: make nand_scan_bbt() static

This implementation detail is no longer needed outside of nand_bbt.c.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/nand/nand_bbt.c

@@ -1074,7 +1074,7 @@ static void verify_bbt_descr(struct mtd_info *mtd, struct nand_bbt_descr *bd)
  * The bad block table memory is allocated here. It must be freed by calling
  * the nand_free_bbt function.
  */
-int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
+static int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 {
 	struct nand_chip *this = mtd->priv;
 	int len, res = 0;

include/linux/mtd/nand.h

@@ -833,7 +833,6 @@ struct nand_manufacturers {
 extern struct nand_flash_dev nand_flash_ids[];
 extern struct nand_manufacturers nand_manuf_ids[];
 
-extern int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd);
 extern int nand_default_bbt(struct mtd_info *mtd);
 extern int nand_markbad_bbt(struct mtd_info *mtd, loff_t offs);
 extern int nand_isreserved_bbt(struct mtd_info *mtd, loff_t offs);