vboot2: Fix flows for TPM_E_MUST_REBOOT

vboot2: Fix flows for TPM_E_MUST_REBOOT

While migrating from vboot1 to vboot2, the tpm_init was moved out of
vboot library and implemented in coreboot. However, while doing this,
the initial factory flow was missed.

We need to ensure following flow for tpm_init:
1. Perform tpm_init
2. If tpm_init fails, set secdata_context flag to indicate to vboot
   that tpm needs reboot.
3. Call vb2_api_phase1
4. If vb2_api_phase1 returns error code saying boot into recovery,
   continue booting into recovery. For all other error codes, save
   context if required and reboot.

[pg: everything but step 2 was already done, so this upstream commit is
quite minimal]

CQ-DEPEND=CL:300572
BUG=chrome-os-partner:45462
BRANCH=None
TEST=Verified behavior on smaug. Steps to test:
1. Reboot into recovery
2. tpmc clear
3. Reboot device

Expected Behavior: Device should reboot after Enabling TPM. Should not
enter recovery

Confirmed that the device behaves as expected.

Change-Id: I72f08d583b744bd77accadd06958c61ade298dfb
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 85ac93137f3cfb28668dcfa18dfc773bf910d44e
Original-Change-Id: I38ab9b9d6c2a718ccc8641377508ffc93fef2ba1
Original-Signed-off-by: Furquan Shaikh <furquan@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/300570
Original-Commit-Ready: Furquan Shaikh <furquan@chromium.org>
Original-Tested-by: Furquan Shaikh <furquan@chromium.org>
Original-Reviewed-by: Randall Spangler <rspangler@chromium.org>
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/12205
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)