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>
[scottwood: Cherry-picked from Linux 8471bb73ba10ed67]
Signed-off-by: Scott Wood <scottwood@freescale.com>
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 552d4d6..cf5cda1 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -238,6 +238,7 @@
 	int (*_lock) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
 	int (*_unlock) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
 	int (*_is_locked) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
+	int (*_block_isreserved) (struct mtd_info *mtd, loff_t ofs);
 	int (*_block_isbad) (struct mtd_info *mtd, loff_t ofs);
 	int (*_block_markbad) (struct mtd_info *mtd, loff_t ofs);
 #ifndef __UBOOT__
@@ -328,6 +329,7 @@
 int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len);
 int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len);
 int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len);
+int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs);
 int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs);
 int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs);