drm/amd/display: Extend w/a for hard hang on HPD to dcn20

[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
for dcn20.

Reviewed-by: Hersen Wu <hersenxs.wu@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>