mtd: introduce mtd_read 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/ar7part.c b/drivers/mtd/ar7part.c
index f40ea45..9453931 100644
--- a/drivers/mtd/ar7part.c
+++ b/drivers/mtd/ar7part.c
@@ -73,8 +73,8 @@
 
 	do { /* Try 10 blocks starting from master->erasesize */
 		offset = pre_size;
-		master->read(master, offset,
-			     sizeof(header), &len, (uint8_t *)&header);
+		mtd_read(master, offset, sizeof(header), &len,
+			 (uint8_t *)&header);
 		if (!strncmp((char *)&header, "TIENV0.8", 8))
 			ar7_parts[1].offset = pre_size;
 		if (header.checksum == LOADER_MAGIC1)
@@ -95,16 +95,16 @@
 	case LOADER_MAGIC1:
 		while (header.length) {
 			offset += sizeof(header) + header.length;
-			master->read(master, offset, sizeof(header),
-				     &len, (uint8_t *)&header);
+			mtd_read(master, offset, sizeof(header), &len,
+				 (uint8_t *)&header);
 		}
 		root_offset = offset + sizeof(header) + 4;
 		break;
 	case LOADER_MAGIC2:
 		while (header.length) {
 			offset += sizeof(header) + header.length;
-			master->read(master, offset, sizeof(header),
-				     &len, (uint8_t *)&header);
+			mtd_read(master, offset, sizeof(header), &len,
+				 (uint8_t *)&header);
 		}
 		root_offset = offset + sizeof(header) + 4 + 0xff;
 		root_offset &= ~(uint32_t)0xff;
@@ -114,8 +114,7 @@
 		break;
 	}
 
-	master->read(master, root_offset,
-		sizeof(header), &len, (u8 *)&header);
+	mtd_read(master, root_offset, sizeof(header), &len, (u8 *)&header);
 	if (header.checksum != SQUASHFS_MAGIC) {
 		root_offset += master->erasesize - 1;
 		root_offset &= ~(master->erasesize - 1);