media: allegro: add support for HEVC encoding

The Allegro Codec supports HEVC encoding. The messages to the MCU are
the same for H.264 and HEVC, but some options have to be changed. These
are actually only a few options.

The driver, however, must add the HEVC VPS/SPS/PPS NAL Units to the
coded stream and must properly provide the HEVC format and controls to
user space.

[hverkuil: fix warning for wrong enum type (h264 instead of hevc)]

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>