mtd: introduce mtd_get_unmapped_area 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/mtdchar.c b/drivers/mtd/mtdchar.c
index 41d64ff..c51f04a 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -1135,7 +1135,7 @@
 		if (offset > mtd->size - len)
 			return (unsigned long) -EINVAL;
 
-		return mtd->get_unmapped_area(mtd, len, offset, flags);
+		return mtd_get_unmapped_area(mtd, len, offset, flags);
 	}
 
 	/* can't map directly */
diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
index 76123bd..b3895cf 100644
--- a/drivers/mtd/mtdconcat.c
+++ b/drivers/mtd/mtdconcat.c
@@ -726,8 +726,8 @@
 			return (unsigned long) -EINVAL;
 
 		if (subdev->get_unmapped_area)
-			return subdev->get_unmapped_area(subdev, len, offset,
-							 flags);
+			return mtd_get_unmapped_area(subdev, len, offset,
+						     flags);
 
 		break;
 	}
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index b09624a..55a9cb5 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -108,8 +108,7 @@
 	struct mtd_part *part = PART(mtd);
 
 	offset += part->offset;
-	return part->master->get_unmapped_area(part->master, len, offset,
-					       flags);
+	return mtd_get_unmapped_area(part->master, len, offset, flags);
 }
 
 static int part_read_oob(struct mtd_info *mtd, loff_t from,