f4f8f4a180366ee90fd8e153213db2cb746ca361 broke ffmpeg compilation with x86
The reason is that ffmpeg's x86 assembly requires at least MMX, which the
pentium CPU_TYPE was preventing.
Fixes ffmpeg compilation on x86_legacy and x86_geode.
Ref: https://github.com/openwrt/openwrt/pull/3061
Signed-off-by: Rosen Penev <rosenp@gmail.com>