drm/amdgpu: Disable PCIE_DPM on Intel RKL Platform

Due to high latency in PCIE clock switching on RKL platforms,
switching the PCIE clock dynamically at runtime can lead to HDMI/DP
audio problems. On newer asics this is handled in the SMU firmware.
For SMU7-based asics, disable PCIE clock switching to avoid the issue.

AMD provide a parameter to disable PICE_DPM.

modprobe amdgpu ppfeaturemask=0xfff7bffb

It's better to contorl PCIE_DPM in amd gpu driver,
switch PCI_DPM by determining intel RKL platform for SMU7-based asics.

Fixes: 1a31474c ("drm/amd/pm: workaround for audio noise issue")
Ref: https://lists.freedesktop.org/archives/amd-gfx/2021-August/067413.html


Signed-off-by: Koba Ko <koba.ko@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>