swscale/x86/rgb2rgb_template: try to fix build without AVX

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

libswscale/x86/rgb2rgb_template.c

@@ -1926,6 +1926,7 @@ static void RENAME(interleaveBytes)(const uint8_t *src1, const uint8_t *src2, ui
 }
 #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
 void RENAME(ff_nv12ToUV)(uint8_t *dstU, uint8_t *dstV,
                                 const uint8_t *unused0,
@@ -1951,6 +1952,7 @@ static void RENAME(deinterleaveBytes)(const uint8_t *src, uint8_t *dst1, uint8_t
             );
 }
 #endif /* !COMPILE_TEMPLATE_AMD3DNOW */
+#endif /* !COMPILE_TEMPLATE_AVX || HAVE_AVX_EXTERNAL */
 
 #if !COMPILE_TEMPLATE_SSE2
 #if !COMPILE_TEMPLATE_AMD3DNOW