swscale/x86/rgb2rgb_template: try to fix build failure with avx disabled

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libswscale/x86/rgb2rgb_template.c

@@ -2525,7 +2525,9 @@ static av_cold void RENAME(rgb2rgb_init)(void)
 #if !COMPILE_TEMPLATE_AMD3DNOW && !COMPILE_TEMPLATE_AVX
     interleaveBytes    = RENAME(interleaveBytes);
 #endif /* !COMPILE_TEMPLATE_AMD3DNOW  && !COMPILE_TEMPLATE_AVX*/
+#if !COMPILE_TEMPLATE_AVX || HAVE_AVX_EXTERNAL
 #if !COMPILE_TEMPLATE_AMD3DNOW && (ARCH_X86_32 || COMPILE_TEMPLATE_SSE2) && COMPILE_TEMPLATE_MMXEXT == COMPILE_TEMPLATE_SSE2 && HAVE_YASM
     deinterleaveBytes  = RENAME(deinterleaveBytes);
 #endif
+#endif
 }