Move TPM code to romstage

Move TPM code to romstage

We want to do TPM initialization as early as possible to keep
the impact on boot time low. Therefore move it to romstage.

Change-Id: I5f2e021e0b11bd70a78ad1f05ec09802d015dd9e
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/856
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>