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>

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hubbub.c

@@ -601,7 +601,8 @@ static const struct hubbub_funcs hubbub2_funcs = {
 	.wm_read_state = hubbub2_wm_read_state,
 	.get_dchub_ref_freq = hubbub2_get_dchub_ref_freq,
 	.program_watermarks = hubbub2_program_watermarks,
-	.allow_self_refresh_control = hubbub1_allow_self_refresh_control
+	.is_allow_self_refresh_enabled = hubbub1_is_allow_self_refresh_enabled,
+	.allow_self_refresh_control = hubbub1_allow_self_refresh_control,
 };
 
 void hubbub2_construct(struct dcn20_hubbub *hubbub,