Avoid an extra var2 in chroma encoding if possible

Also remove a redundant if.

encoder/analyse.c

@@ -2637,9 +2637,8 @@ intra_analysis:
             h->mb.i_partition = D_16x16;
             assert( h->mb.cache.pskip_mv[1] <= h->mb.mv_max_spel[1] || h->i_thread_frames == 1 );
             /* Set up MVs for future predictors */
-            if( b_skip )
-                for( int i = 0; i < h->mb.pic.i_fref[0]; i++ )
-                    M32( h->mb.mvr[0][i][h->mb.i_mb_xy] ) = 0;
+            for( int i = 0; i < h->mb.pic.i_fref[0]; i++ )
+                M32( h->mb.mvr[0][i][h->mb.i_mb_xy] ) = 0;
         }
         else
         {

encoder/macroblock.c

@@ -331,7 +331,8 @@ void x264_mb_encode_8x8_chroma( x264_t *h, int b_inter, int i_qp )
     {
         int thresh = (x264_lambda2_tab[i_qp] + 32) >> 6;
         int ssd[2];
-        int score  = h->pixf.var2_8x8( h->mb.pic.p_fenc[1], FENC_STRIDE, h->mb.pic.p_fdec[1], FDEC_STRIDE, &ssd[0] );
+        int score = h->pixf.var2_8x8( h->mb.pic.p_fenc[1], FENC_STRIDE, h->mb.pic.p_fdec[1], FDEC_STRIDE, &ssd[0] );
+        if( score < thresh*4 )
             score += h->pixf.var2_8x8( h->mb.pic.p_fenc[2], FENC_STRIDE, h->mb.pic.p_fdec[2], FDEC_STRIDE, &ssd[1] );
         if( score < thresh*4 )
         {