tpm2-sys: Remove dependency on num_cpus
tpm2-sys: Remove dependency on num_cpus

It's no longer used, and pulling in the crate hermit-abi
which does causes problems in Kokoro with the latest update.

BUG=b:210037151
TEST=./tools/presubmit

Change-Id: I0344ea32dcc97923bb7b0010a6e5c33003598df0
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3328943
Reviewed-by: Daniel Verkamp <72bc170b46ec491f7bdd4359a1c0bfed274de40c@chromium.org>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Anton Romanov <7c8c28e1283c1d87f2c3df4d6b5c74b6ae02bcd9@google.com>
Commit-Queue: Dennis Kempin <cd09796fb571bec2782819dbfd33307f65b1c778@google.com>

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