hevc: eliminate unnecessary cbf_c{b,r} arrays
- They are be replaced by passing additional parameters to the transform
functions.
- Adaptation to 4:2:2

Signed-off-by: Mickaël Raulet <mraulet@insa-rennes.fr>
hevc: fix skip_flag
hevc: remove non necessary parameters to ff_hevc_set_qpy
hevc: do not store the transform inter_split flag in the context