hevc/mvs: simplifying derive_spatial_merge_candidates function

cherry picked from commit 99be11cf08a5628d0bb6ac7f4958bf9dd35cda62

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
hevc/mvs: code cleaning

cherry picked from commit 74f10da013ea71a3f6b77cdff989c4574c8a5ea2

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
hevc/mvs: more cleanups

cherry picked from commit c4e467e79f59453783c97bc6044082edb7a6468b

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
hevc/mvs: cosmetics

cherry picked from commit 9053cd92700e939cde49ab0ea3c6917be453cab7

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
hevc: cleaning up SSE2 and SSSE3 deblocking filters

Signed-off-by: Mickaël Raulet <mraulet@insa-rennes.fr>

cherry picked from commit b432041d7d1eca38831590f13b4e5baffff8186f
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>