drm/amd/display: fix DalDramClockChangeLatencyNs override

[why]
pstate_latency_us never gets updated from the hard coded value
in rn_clk_mgr.c

[how]
update the wm table's values before we do calculations with them

Signed-off-by: Joseph Gravenor <joseph.gravenor@amd.com>
Reviewed-by: Eric Yang <eric.yang2@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>