yv12config: fix highbitdepth build

Change-Id: Ie8a4caae19fb514d5bd22e0ae35ca0edcd3484ae
vp9_spatial_svc_encoder: fix -bit-depth arg parsing

use arg_parse_enum_or_int like vpxenc. this also fixes a warning as
arg_parse_enum is not currently declared in args.h.

Change-Id: If9ce258d6adb6286eb86f529083929d5fe2b3a56
args.h: add arg_parse_enum prototype

Change-Id: I64d6e7c2d3f76528ab409ce381267fc5cef13ab1
Merge "yv12config: fix highbitdepth build"
Merge "vp9_spatial_svc_encoder: fix -bit-depth arg parsing"
Merge "args.h: add arg_parse_enum prototype"