swscale/x86/yuv2rgb: Remove unused ASM constants

mmx_grnmask is unused since 531f97b0c32d1d421f3ac614e002c53951658115,
the other constants since e934194b6a.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libswscale/x86/yuv2rgb.c

@@ -41,14 +41,6 @@
 
 #define DITHER1XBPP // only for MMX
 
-/* hope these constant values are cache line aligned */
-DECLARE_ASM_CONST(8, uint64_t, mmx_00ffw)   = 0x00ff00ff00ff00ffULL;
-DECLARE_ASM_CONST(8, uint64_t, mmx_redmask) = 0xf8f8f8f8f8f8f8f8ULL;
-DECLARE_ASM_CONST(8, uint64_t, mmx_grnmask) = 0xfcfcfcfcfcfcfcfcULL;
-DECLARE_ASM_CONST(8, uint64_t, pb_e0) = 0xe0e0e0e0e0e0e0e0ULL;
-DECLARE_ASM_CONST(8, uint64_t, pb_03) = 0x0303030303030303ULL;
-DECLARE_ASM_CONST(8, uint64_t, pb_07) = 0x0707070707070707ULL;
-
 //MMX versions
 #if HAVE_MMX
 #undef RENAME