mtd: introduce mtd_unpoint interface

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 5b66472..b09624a 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -97,7 +97,7 @@
 {
 	struct mtd_part *part = PART(mtd);
 
-	part->master->unpoint(part->master, from + part->offset, len);
+	mtd_unpoint(part->master, from + part->offset, len);
 }
 
 static unsigned long part_get_unmapped_area(struct mtd_info *mtd,