Removed redundant checks of the mode_info_context flags

Code cleanup.  The build inter predictor functions are
redundantly checking the mode_info_context for either
INTRA_FRAME or SPLITMV.

Change-Id: I4d58c3a5192a4c2cec5c24ab1caf608bf13aebfb

vp8/decoder/threading.c

@@ -122,7 +122,7 @@ static void decode_macroblock(VP8D_COMP *pbi, MACROBLOCKD *xd, int mb_row, int m
         }
         else
         {
-            vp8_build_inter_predictors_mb_s(xd);
+            vp8_build_inter16x16_predictors_mb_s(xd);
         }
         return;
     }