Change datatype of local variable delta_lf

Changed the datatype of local variable 'delta_lf' in
av1_get_filter_level() from int to int8_t for consistency

Change-Id: Ic5c63fca033bbcfa227d924555e00f6d85931539
diff --git a/av1/common/av1_loopfilter.c b/av1/common/av1_loopfilter.c
index ee01a82..69ad113 100644
--- a/av1/common/av1_loopfilter.c
+++ b/av1/common/av1_loopfilter.c
@@ -64,7 +64,7 @@
                              int plane, const MB_MODE_INFO *mbmi) {
   const int segment_id = mbmi->segment_id;
   if (cm->delta_q_info.delta_lf_present_flag) {
-    int delta_lf;
+    int8_t delta_lf;
     if (cm->delta_q_info.delta_lf_multi) {
       const int delta_lf_idx = delta_lf_id_lut[plane][dir_idx];
       delta_lf = mbmi->delta_lf[delta_lf_idx];