drm/amd/display: Apply w/a for hard hang on HPD

[Why]
HPD disable and enable sequences are not mutually exclusive
on Linux. For HPDs that spans under 1s (i.e. HPD low = 1s),
part of the disable sequence (specifically, a request to SMU
to lower refclk) could come right before the call to PHY
enablement, causing DMUB to access an irresponsive PHY
and thus a hard hang on the system.

[How]
Disable 48mhz refclk off when there is any HPD status in
connected state.

Reviewed-by: Hersen Wu <hersenwu@amd.com>
Acked-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>