drm/amd/display: Choose HUBP unbounded request based on DML output

[why]
Previously, we decide on the unbounded request
purely based on pipe_cnt which is a wrong variable
to use to determine how many pipes are in "use".
DML already accounts for number of pipes in use
along with other various factors and is a more reliable
method of determination.

[how]
Use UnboundedRequestEnabledThisState to decide
on unbounbded_req_enabled.

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Sung Joon Kim <sungjoon.kim@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>