x86_64: acpi: disable PM timer in forwarded FADT
x86_64: acpi: disable PM timer in forwarded FADT

There is currently no use case for the PM timer in the guest and TMR_STS
is not implemented in vPM1, so disable it altogether for now.

BUG=b:199383670
TEST=boot manatee

Change-Id: I61b214a466becef2d923fdbfe450c31b08b70037
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3528533
Reviewed-by: Daniel Verkamp <72bc170b46ec491f7bdd4359a1c0bfed274de40c@chromium.org>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Commit-Queue: Daniel Verkamp <72bc170b46ec491f7bdd4359a1c0bfed274de40c@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm