staging: lustre: Use 'kvfree()' for memory allocated by 'kvzalloc()'

'buf' is allocated with 'kvzalloc()'. 'kvfree()' must be used to free it.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Fixes: 11c647ca ("staging: lustre: obdclass: variable llog chunk size")
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/obdclass/llog.c

@@ -385,7 +385,7 @@ static int llog_process_thread(void *arg)
 	if (cd)
 		cd->lpcd_last_idx = last_called_index;
 
-	kfree(buf);
+	kvfree(buf);
 	lpi->lpi_rc = rc;
 	return 0;
 }