staging: erofs: rename superblock flags (MS_xyz -> SB_xyz)

This patch follows commit 1751e8a6 ("Rename superblock
flags (MS_xyz -> SB_xyz)") and after commit ("vfs: Suppress
MS_* flag defs within the kernel unless explicitly enabled"),
there is no MS_RDONLY and MS_NOATIME at all.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/erofs/super.c

@@ -340,7 +340,7 @@ static int erofs_read_super(struct super_block *sb,
 		goto err_sbread;
 
 	sb->s_magic = EROFS_SUPER_MAGIC;
-	sb->s_flags |= MS_RDONLY | MS_NOATIME;
+	sb->s_flags |= SB_RDONLY | SB_NOATIME;
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
 	sb->s_time_gran = 1;
 
@@ -627,7 +627,7 @@ static int erofs_remount(struct super_block *sb, int *flags, char *data)
 {
 	BUG_ON(!sb_rdonly(sb));
 
-	*flags |= MS_RDONLY;
+	*flags |= SB_RDONLY;
 	return 0;
 }