drm/amd: Use amdgpu_device_pcie_dynamic_switching_supported() for SMU7

SMU7 does a check if the dGPU is inserted into a Rocket Lake system,
to turn off DPM.  Extend this check to all systems that have problems
with dynamic switching by using the
amdgpu_device_pcie_dynamic_switching_supported() helper.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>