drm/i915/mtl: memory latency data from LATENCY_LPX_LPY for WM

Since Xe LPD+, Memory latency data are in LATENCY_LPX_LPY registers
instead of GT driver mailbox.

v2: Use the extracted wm latency adjustment function(Matt)
v3: Use Odd/even for Latency fields(MattR)

Bspec: 64608

Cc: Matt Roper <matthew.d.roper@intel.com>
Original Author: Caz Yokoyama
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/<20220818234202.451742-15-radhakrishna.sripada@intel.com>