coreboot: check Cr50 PM mode on normal boot

Under some scenarios the key ladder on the Cr50 can get disabled.  If
this state is detected, trigger a reboot of the Cr50 to restore full
TPM functionality.

BUG=b:121463033
BRANCH=none
TEST=Built coreboot on sarien and grunt platforms.
TEST=Ran 'gsctool -a -m disable' and reboot. Verified coreboot sends
VENDOR_CC_IMMEDIATE_RESET command to Cr50 and that the Cr50 resets and
then the platform boots normally.
TEST=Performed Cr50 rollback to 0.0.22 which does not support the
VENDOR_CC_TPM_MODE command, confirmed that platform boots normally and
the coreboot log captures the unsupported command.
Tested-by: Keith Short <keithshort@chromium.org>

Change-Id: I70e012efaf1079d43890e909bc6b5015bef6835a
Signed-off-by: Keith Short <keithshort@chromium.org>
Reviewed-on: https://review.coreboot.org/c/31260
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/include/elog.h

@@ -223,6 +223,9 @@ struct elog_event_mem_cache_update {
 #define  ELOG_SLEEP_PENDING_PM1_WAKE       0x01
 #define  ELOG_SLEEP_PENDING_GPE0_WAKE      0x02
 
+/* Cr50 reset to enable TPM */
+#define ELOG_TYPE_CR50_NEED_RESET         0xb2
+
 struct elog_event_extended_event {
 	u8 event_type;
 	u32 event_complement;