drm/amd/pm: workaround for audio noise issue

stable inclusion
from stable-5.10.27
commit e02f765fa784b7bf121451b8e2af2a69676a7710
bugzilla: 51493

--------------------------------

commit 9d03730e upstream.

On some Intel platforms, audio noise can be detected due to
high pcie speed switch latency.
This patch leaverages ppfeaturemask to fix to the highest pcie
speed then disable pcie switching.

v2:
coding style fix

Signed-off-by: Kenneth Feng <kenneth.feng@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by:   Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>