mainboard/google/sarien: skip tpm check when !verstage

mainboard/google/sarien: skip tpm check when !verstage

The TPM driver isn't loaded in other stages but verstage so when we try
to communicate with the TPM it fails. We don't need to communicate with
it anyway since the TPM won't continue to tell us that recovery was
requested, only the first query responds with the recovery request.

BRANCH=none
BUG=b:129150074,b:123360379
TEST=1)boot arcada without recovery and notice that the "tpm transaction
failed" log lines are no longer present. 2) boot into recovery using the
ESC refresh power key combination and verify that the recovery reason
was "recovery button pressed"

Change-Id: I13284483d069ed50b0d16b36d0120d006485f7f4
Signed-off-by: Jett Rink <jettrink@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32030
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Keith Short <keithshort@chromium.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>