x86: h264dsp: Fix link failure with optimizations disabled

With optimzations disabled compilers have trouble doing dead code
elimination on 'if (foo && 0)' expressions, while 'if (0 && foo)'
still works, so use the latter to avoid problems.

Bug-Id: 707

libavcodec/x86/h264dsp_init.c

@@ -212,7 +212,7 @@ av_cold void ff_h264dsp_init_x86(H264DSPContext *c, const int bit_depth,
 {
     int cpu_flags = av_get_cpu_flags();
 
-    if (chroma_format_idc <= 1 && EXTERNAL_MMXEXT(cpu_flags))
+    if (EXTERNAL_MMXEXT(cpu_flags) && chroma_format_idc <= 1)
         c->h264_loop_filter_strength = ff_h264_loop_filter_strength_mmxext;
 
     if (bit_depth == 8) {