mpegvideo: Replace arch initialization ifdeffery by standard conditionals

libavcodec/mpegvideo.c

@@ -165,17 +165,16 @@ av_cold int ff_dct_common_init(MpegEncContext *s)
         s->dct_unquantize_mpeg2_intra = dct_unquantize_mpeg2_intra_bitexact;
     s->dct_unquantize_mpeg2_inter = dct_unquantize_mpeg2_inter_c;
 
-#if ARCH_X86
-    ff_MPV_common_init_x86(s);
-#elif ARCH_ALPHA
+    if (ARCH_ALPHA)
         ff_MPV_common_init_axp(s);
-#elif ARCH_ARM
+    if (ARCH_ARM)
         ff_MPV_common_init_arm(s);
-#elif ARCH_BFIN
+    if (ARCH_BFIN)
         ff_MPV_common_init_bfin(s);
-#elif ARCH_PPC
+    if (ARCH_PPC)
         ff_MPV_common_init_ppc(s);
-#endif
+    if (ARCH_X86)
+        ff_MPV_common_init_x86(s);
 
     /* load & permutate scantables
      * note: only wmv uses different ones