drm/amd: Fix shutdown (again) on some SMU v13.0.4/11 platforms

commit cd94d1b1 ("dm/amd/pm: Fix problems with reboot/shutdown for
some SMU 13.0.4/13.0.11 users") attempted to fix shutdown issues
that were reported since commit 31729e8c

 ("drm/amd/pm: fixes a
random hang in S4 for SMU v13.0.4/11") but caused issues for some
people.

Adjust the workaround flow to properly only apply in the S4 case:
-> For shutdown go through SMU_MSG_PrepareMp1ForUnload
-> For S4 go through SMU_MSG_GfxDeviceDriverReset and
   SMU_MSG_PrepareMp1ForUnload

Reported-and-tested-by: lectrode <electrodexsnet@gmail.com>
Closes: https://github.com/void-linux/void-packages/issues/50417
Cc: stable@vger.kernel.org
Fixes: cd94d1b1

 ("dm/amd/pm: Fix problems with reboot/shutdown for some SMU 13.0.4/13.0.11 users")
Reviewed-by: Tim Huang <Tim.Huang@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>