generate_gypi.sh: --disable-avx and --only-config flags

source/config/win/x64/vpx_config.c

Index: source/config/win/x64/vpx_config.c
diff --git a/source/config/win/x64/vpx_config.c b/source/config/win/x64/vpx_config.c
index 6dd3005d3c5c214227bcdfa7995d4fed67633b78..9e18ea7ae14a3c52fdca750a8c566d12c84bfb60 100644
--- a/source/config/win/x64/vpx_config.c
+++ b/source/config/win/x64/vpx_config.c
@@ -6,5 +6,5 @@
 /* in the file PATENTS.  All contributing project authors may */
 /* be found in the AUTHORS file in the root of the source tree. */
 #include "vpx/vpx_codec.h"
-static const char* const cfg = "--target=x86_64-win64-vs12 --enable-realtime-only --enable-external-build --enable-postproc --disable-install-srcs --enable-multi-res-encoding --enable-temporal-denoising --disable-unit-tests --disable-install-docs --disable-examples --enable-vp9-temporal-denoising --enable-vp9-postproc --size-limit=16384x16384";
+static const char* const cfg = "--target=x86_64-win64-vs12 --enable-realtime-only --enable-external-build --enable-postproc --disable-install-srcs --enable-multi-res-encoding --enable-temporal-denoising --disable-unit-tests --disable-install-docs --disable-examples --enable-vp9-temporal-denoising --enable-vp9-postproc --size-limit=16384x16384 --disable-avx --disable-avx2";
 const char *vpx_codec_build_config(void) {return cfg;}