media: meson: vdec: add helpers for lossless framebuffer compression buffers

Add helpers to support the lossless framebuffer compression format that
will be used in HEVC & VP9 decoders when decoding 10bit content for
downsampling to 8bit NV12 and later proper compressed buffer support.

Signed-off-by: Maxime Jourdan <mjourdan@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>