xvmc.h used FF_API_* macros before, but they were removed in
1c63aed232febf4404659bf006237ee4f7f17c9c, leaving the include
unused.
The ones in android_camera.c and mediacodec_wrapper.c have been
added due to a misunderstanding, fixed in
c0bce367e4932f0fb09195e6978ac1a5a60480a4 and
13b77af2f0b56d6c87bb147947337981c21f4245.
The one in mediacodec.c seems to never have been used at all.
Signed-off-by: Martin Storsjö <martin@martin.st>