Fix linking if MMX is disabled.

Originally committed as revision 23839 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h264pred.c

@@ -1299,5 +1299,5 @@ void ff_h264_pred_init(H264PredContext *h, int codec_id){
     h->pred16x16_add[ HOR_PRED8x8]= pred16x16_horizontal_add_c;
 
     if (ARCH_ARM) ff_h264_pred_init_arm(h, codec_id);
-    if (ARCH_X86) ff_h264_pred_init_x86(h, codec_id);
+    if (HAVE_MMX) ff_h264_pred_init_x86(h, codec_id);
 }

libavcodec/vp8dsp.c

@@ -452,6 +452,6 @@ av_cold void ff_vp8dsp_init(VP8DSPContext *dsp)
     VP8_BILINEAR_MC_FUNC(1, 8);
     VP8_BILINEAR_MC_FUNC(2, 4);
 
-    if (ARCH_X86)
+    if (HAVE_MMX)
         ff_vp8dsp_init_x86(dsp);
 }