ffmpeg: disable assembly on MIPS

Disable use of assembly on MIPS to allow it to build. MIPS is not
expected to be high performance in OpenWrt, and this allows it to still
be used for media identification as updated versions of ffmpeg are
brought in.

The error is in

libavcodec/mips/aacdec_mips.c: In function 'imdct_and_windowing_mips'

regarding: 'asm' has impossible constraints in multiple locations.

Signed-off-by: Ian Leonard <antonlacon@gmail.com>

multimedia/ffmpeg/Makefile

@@ -453,10 +453,13 @@ FFMPEG_CONFIGURE+= \
 else ifneq ($(findstring powerpc,$(CONFIG_ARCH)),)
 FFMPEG_CONFIGURE+= \
 	--disable-altivec
-# libavcode/mips/aacdec_mips.c build problem
-else ifneq ($(findstring 24kf,$(CONFIG_CPU_TYPE)),)
+endif
+
+# libavcodec/mips/aacdec_mips.c build problem
+# XXX: disable use of assembly on MIPS. Patches welcome.
+ifneq ($(findstring mips,$(CONFIG_ARCH)),)
 FFMPEG_CONFIGURE+= \
-	--disable-inline-asm
+        --disable-asm --disable-inline-asm
 endif
 
 # selectively disable optimizations according to arch/cpu type