UBIFS: remove xattr Kconnfig option

Remove CONFIG_UBIFS_FS_XATTR configuration option and associated
UBIFS_FS_XATTR ifdefs.

Testing:
       Tested using integck while using nandsim on x86 & MX28 based
       platform with Micron MT29F2G08ABAEAH4 nand.

Signed-off-by: Subodh Nijsure <snijsure@grid-net.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

fs/ubifs/journal.c

@@ -1267,7 +1267,6 @@ out_free:
 	return err;
 }
 
-#ifdef CONFIG_UBIFS_FS_XATTR
 
 /**
  * ubifs_jnl_delete_xattr - delete an extended attribute.
@@ -1462,4 +1461,3 @@ out_free:
 	return err;
 }
 
-#endif /* CONFIG_UBIFS_FS_XATTR */