x86: dnxhdenc: Eliminate some unnecessary ifdefs

libavcodec/x86/dnxhdenc_init.c

@@ -30,10 +30,8 @@ void ff_get_pixels_8x4_sym_sse2(int16_t *block, const uint8_t *pixels,
 
 av_cold void ff_dnxhdenc_init_x86(DNXHDEncContext *ctx)
 {
-#if HAVE_SSE2_EXTERNAL
     if (EXTERNAL_SSE2(av_get_cpu_flags())) {
         if (ctx->cid_table->bit_depth == 8)
             ctx->get_pixels_8x4_sym = ff_get_pixels_8x4_sym_sse2;
     }
-#endif /* HAVE_SSE2_EXTERNAL */
 }