Enable PD communication in RO for external display

This patch makes EC enable PD communication if it's running in
manual recovery mode. This is required to show recovery screen
on a type-c monitor.

This patch also makes EC-EFS ignore power availability. It will
make EC verify & jump to RW even if power is sourced by a barrel
jack adapter. This should allow depthcharge to show screens
(e.g. broken, warning) on a type-c monitor.

BUG=b:72387533
BRANCH=none
TEST=On Fizz with type-c monitor, verify
- Recovery screen is displayed in manual recovery mode.
- Critical update screen is displayed in normal mode.
- Warning screen is displayed in developer mode.
Monitors tested: Dingdong, Dell S2718D

Change-Id: Ib53e02d1e5c0f5b2d96d9a02fd33022f92e52b04
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/898346
Reviewed-by: Randall Spangler <rspangler@chromium.org>

include/vboot.h

@@ -46,3 +46,15 @@ int vboot_is_padding_valid(const uint8_t *data, uint32_t start, uint32_t end);
  */
 int vboot_verify(const uint8_t *data, int len,
 		 const struct rsa_public_key *key, const uint8_t *sig);
+
+/**
+ * Entry point of EC EFS
+ */
+void vboot_main(void);
+
+/**
+ * Get if vboot requires PD comm to be enabled or not
+ *
+ * @return 1: need PD communication. 0: PD communication is not needed.
+ */
+int vboot_need_pd_comm(void);