drm/amd/display: Adding forgotten hubbub func

[why]
While doing seamless boot I made some changes
to dcn2 hubbub functions, missed a link

[how]
link hubbub1 func to hubbub2 usage. It has already
been successfully linked in dcn1 and 3.

Signed-off-by: Martin Leung <martin.leung@amd.com>
Reviewed-by: Alvin Lee <Alvin.Lee2@amd.com>
Acked-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>