mtd: introduce mtd_read interface

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/tests/mtd_readtest.c

@@ -52,7 +52,7 @@ static int read_eraseblock_by_page(int ebnum)
 
 	for (i = 0; i < pgcnt; i++) {
 		memset(buf, 0 , pgcnt);
-		ret = mtd->read(mtd, addr, pgsize, &read, buf);
+		ret = mtd_read(mtd, addr, pgsize, &read, buf);
 		if (ret == -EUCLEAN)
 			ret = 0;
 		if (ret || read != pgsize) {