mtd: add an ioctl to query the lock status of a flash sector

This patchs adds a way for user space programs to find out whether a
flash sector is locked. An optional driver method in the mtd_info struct
provides the information.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 5326435..43b7d72 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -216,6 +216,7 @@
 	/* Chip-supported device locking */
 	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);
 
 	/* Power Management functions */
 	int (*suspend) (struct mtd_info *mtd);