Revert "iommu/amd: Fix performance counter initialization"

This reverts commit 6778ff5b.

The original commit tries to address an issue, where PMC power-gating
causing the IOMMU PMC pre-init test to fail on certain desktop/mobile
platforms where the power-gating is normally enabled.

There have been several reports that the workaround still does not
guarantee to work, and can add up to 100 ms (on the worst case)
to the boot process on certain platforms such as the MSI B350M MORTAR
with AMD Ryzen 3 2200G.

Therefore, revert this commit as a prelude to removing the pre-init
test.

Link: https://lore.kernel.org/linux-iommu/alpine.LNX.3.20.13.2006030935570.3181@monopod.intra.ispras.ru/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201753


Cc: Tj (Elloe Linux) <ml.linux@elloe.vision>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Alexander Monakov <amonakov@ispras.ru>
Cc: David Coe <david.coe@live.co.uk>
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Link: https://lore.kernel.org/r/20210409085848.3908-2-suravee.suthikulpanit@amd.com


Signed-off-by: Joerg Roedel <jroedel@suse.de>