libavcodec: Don't include libavcodec/x86/vvc/Makefile on any architecture

This currently builds files in the libavcodec/x86/{vvc,h26x}
subdirectories, which is somewhat unexpected when building for
another architecture than x86.

The regular arch subdirectories are handled with

    -include $(SRC_PATH)/$(1)/$(ARCH)/Makefile

in the toplevel Makefile. Switch this to a similar optional
inclusion, using $(ARCH).

Signed-off-by: Martin Storsjö <martin@martin.st>

libavcodec/Makefile

@@ -64,7 +64,7 @@ OBJS = ac3_parser.o                                                     \
 
 # subsystems
 include $(SRC_PATH)/libavcodec/vvc/Makefile
-include $(SRC_PATH)/libavcodec/x86/vvc/Makefile
+-include $(SRC_PATH)/libavcodec/$(ARCH)/vvc/Makefile
 OBJS-$(CONFIG_AANDCTTABLES)            += aandcttab.o
 OBJS-$(CONFIG_AC3DSP)                  += ac3dsp.o ac3.o ac3tab.o
 OBJS-$(CONFIG_ADTS_HEADER)             += adts_header.o mpeg4audio_sample_rates.o