Patch to support VP9 encoding with new profiles 1-3.
Profile 1 (8-bit 422/444) should work with default libvpx
configuration.
However you will need to configure libvpx with
--enable-vp9-highbitdepth before building and linking
with ffmpeg for profile 2 (10-/12-bit 420) and profile 3
(10-/12-bit 422/444) encoding.

You may use the appropriate profile option on the
command line:
-profile:v 1 for 422/444 8-bit encoding
-profile:v 2 for 420 10-/12- bit encoding
-profile:v 3 for 422/444 10-/12-bit encoding
If you do not use the -profile:v option, it will be deduced
from the source format.
Signed-off-by: James Zern <jzern@google.com>