[Why]
A hubp pointer was being passed to DCN1 functions, which
expect the enclosing structure (for the purpose of container_of macros)
to be dcn10_hubp, but the actual type was dcn20_hubp.

[How]
Copy existing DCN1 functions and alter them slightly for use with
dcn20_hubp.
Signed-off-by: Ilya Bakoulin <Ilya.Bakoulin@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>