ubifs: introduce Kconfig symbol for xattr support

Allow to disable extended attribute support.

This aids in reliability testing, especially since some xattr
related bugs have surfaced.

Also an embedded system might not need it, so this allows for a
slightly smaller kernel (about 4KiB).

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Richard Weinberger <richard@nod.at>

fs/ubifs/super.c

@@ -2053,7 +2053,9 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
 	if (c->max_inode_sz > MAX_LFS_FILESIZE)
 		sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
 	sb->s_op = &ubifs_super_operations;
+#ifdef CONFIG_UBIFS_FS_XATTR
 	sb->s_xattr = ubifs_xattr_handlers;
+#endif
 #ifdef CONFIG_UBIFS_FS_ENCRYPTION
 	sb->s_cop = &ubifs_crypt_operations;
 #endif