mtd: Introduce mtd_block_isreserved()

In addition to mtd_block_isbad(), which checks if a block is bad or
reserved, it's needed to check if a block is reserved only (but not
bad). This commit adds an MTD interface for it, in a similar fashion to
mtd_block_isbad().

While here, fix mtd_block_isbad() so the out-of-bounds checking is done
before the callback check.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Tested-by: Pekon Gupta <pekon@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 2f0af28..1cff329 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -810,6 +810,7 @@
 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);
 extern int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt);
 extern int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
 			   int allowbbt);