rename always_inline to av_always_inline and move to common.h

libavcodec/bitstream.h

libavcodec/bytestream.h

libavcodec/cabac.h

libavcodec/dv.c

libavcodec/faandct.c

libavcodec/ffv1.c

libavcodec/h264.c

libavcodec/h264idct.c

libavcodec/i386/fdct_mmx.c

libavcodec/jfdctfst.c

libavcodec/jfdctint.c

libavcodec/mathops.h

libavcodec/motion_est.c

libavcodec/motion_est_template.c

libavcodec/mpeg12.c

libavcodec/mpegvideo.c

libavcodec/pthread.c

libavcodec/smacker.c

libavcodec/snow.c

libavcodec/snow.h