package/omxplayer: new package

package/omxplayer: new package

OMXplayer uses openMAX on the RPi to play videos with hardware
acceleration.

Compared to using a gstreamer pipe, OMXplayer uses a complete
"tunnel-mode", in which the video is piped (after demuxing) into the
hardware, all the way down to the display, whereas gstreamer composes
the video using the eglgles sink, which uses mem-to-mem copies.

So, when playing a locally-stored 1080p video, OMXplayer averages 20%
(with peaks up to ~30%, depending on the complexity of the video) CPU,
while gstreamer bursts up to 40+% when playing 720p and totally chokes
on a 1080p video; all on an non-overclocked RPi-1.

Note that we have to depend on rpi-userland. rpi-userland is a GLES/EGL
provider, so it can't be selected (as all providers of a virtual package
can't).

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
[Thomas: add a depends on BR2_PACKAGE_FFMPEG_ARCH_SUPPORTS.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>