mtd: do not use mtd->lock, unlock and is_locked directly

Instead, call the corresponding MTD API function which will return
'-EOPNOTSUPP' if the operation is not supported.

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 23a51104..92da621 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -814,10 +814,7 @@
 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
 			return -EFAULT;
 
-		if (!mtd->lock)
-			ret = -EOPNOTSUPP;
-		else
-			ret = mtd_lock(mtd, einfo.start, einfo.length);
+		ret = mtd_lock(mtd, einfo.start, einfo.length);
 		break;
 	}
 
@@ -828,10 +825,7 @@
 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
 			return -EFAULT;
 
-		if (!mtd->unlock)
-			ret = -EOPNOTSUPP;
-		else
-			ret = mtd_unlock(mtd, einfo.start, einfo.length);
+		ret = mtd_unlock(mtd, einfo.start, einfo.length);
 		break;
 	}
 
@@ -842,10 +836,7 @@
 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
 			return -EFAULT;
 
-		if (!mtd->is_locked)
-			ret = -EOPNOTSUPP;
-		else
-			ret = mtd_is_locked(mtd, einfo.start, einfo.length);
+		ret = mtd_is_locked(mtd, einfo.start, einfo.length);
 		break;
 	}