drm/amd/display: Reduce HPD Detection Interval for IPS

Fix DP Compliance test 4.2.1.3, 4.2.2.8, 4.3.1.12, 4.3.1.13
when IPS enabled.

Original HPD detection interval is set to 5s which violates DP
compliance.
Reduce the interval parameter, such that link training can be
finished within 5 seconds.

Fixes: afca033f ("drm/amd/display: Add periodic detection for IPS")
Reviewed-by: Roman Li <roman.li@amd.com>
Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>