package/ffmpeg: fix build on riscv32

Ported patch from OpenEmbedded:
https://github.com/openembedded/openembedded-core/commit/010b068bcc126dbbc1e2032997e8d83360a7de35

"ffmpeg 6.0 has added assembly routines which uses rv64i ISA
unconditionally, ideally it should check for ISA before using those
instructions."

Fixes:
https://autobuild.buildroot.org/results/8a7082a0f24ebcf264aeac5e0fea704dc6a6bb1c/

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/ffmpeg/ffmpeg.mk

@@ -529,6 +529,11 @@ else
 FFMPEG_CONF_OPTS += --disable-altivec
 endif
 
+# Fix build failure on several missing assembly instructions
+ifeq ($(BR2_RISCV_32),y)
+FFMPEG_CONF_OPTS += --disable-rvv --disable-asm
+endif
+
 # Uses __atomic_fetch_add_4
 ifeq ($(BR2_TOOLCHAIN_HAS_LIBATOMIC),y)
 FFMPEG_CONF_OPTS += --extra-libs=-latomic