media: hantro: Fix G2/HEVC negotiated pixelformat

G2/HEVC is broken because driver capture queue pixelformat ioctl G_FMT
returns VT12 while G2/HEVC always generate NV12 frames:

video1: VIDIOC_S_FMT: type=vid-out-mplane, width=2560, height=1600, format=S265 little-endian (0x35363253), field=none, colorspace=0, num_planes=1, flags=0x0, ycbcr_enc=0, quantization=0, xfer_func=0
plane 0: bytesperline=0 sizeimage=6144000
video1: VIDIOC_S_EXT_CTRLS: which=0x0, count=1, error_idx=0, request_fd=0, name=HEVC Sequence Parameter Set, id/size=0x990cf0/32
video1: VIDIOC_G_FMT: type=vid-cap-mplane, width=2560, height=1600, format=VT12 little-endian (0x32315456), field=none, colorspace=0, num_planes=1, flags=0x0, ycbcr_enc=0, quantization=0, xfer_func=0
plane 0: bytesperline=2560 sizeimage=6144000
video1: VIDIOC_ENUM_FMT: index=0, type=vid-cap-mplane, flags=0x0, pixelformat=NV12 little-endian (0x3231564e), mbus_code=0x0000, description='Y/CbCr 4:2:0'
video1: VIDIOC_ENUM_FMT: error -22: index=1, type=vid-cap-mplane, flags=0x0, pixelformat=.... little-endian (0x00000000), mbus_code=0x0000, description=''
video1: VIDIOC_G_FMT: type=vid-cap-mplane, width=2560, height=1600, format=VT12 little-endian (0x32315456), field=none, colorspace=0, num_planes=1, flags=0x0, ycbcr_enc=0, quantization=0, xfer_func=0

Use the postprocessor functions introduced by Hantro G2/VP9 codec series
to fix the issue and remove duplicated buffer management.
This allow Hantro G2/HEVC to produce NV12_4L4 and NV12.

Fluster scores are 77/147 for HEVC and 129/303 for VP9 (no regression).

Beauty, Jockey and ShakeNDry bitstreams from UVG (http://ultravideo.fi/

)
set have also been tested.

Fixes: 53a3e710 ("media: hantro: Simplify postprocessor")
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>