yorp: Add tcpc alert handling
yorp: Add tcpc alert handling

This CL adds required code to the tcpc_alert_event() and
tcpc_get_alert_status() functions. In addition, it adds
board_tcpc_init().

The ANX7447 does not have an EC controlled reset line. Other than that
modification the actions taken in tcpc_alert_event and
tcpc_get_alert_status are the same as what's been done of previous
projects using these TCPCs.

board_reset_pd_mcu still needs to be implemented, but is not related
to the tcpc_alert_event() and tcpc_get_alert_status() functions. Also,
at this point ANX7447 is not supported as that depends on the driver
landing.

BUG=b:74127309
BRANCH=none
TEST=Verifed that with external charger that USB PD state machine
advances to SNK_READY state. Note that port 0 does not work at all in
this version.

Change-Id: Ib887b4dba6bacb4b3fb6e03f634362e1c3aa4da2
Signed-off-by: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@google.com>
Reviewed-on: https://chromium-review.googlesource.com/982518
Commit-Ready: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@chromium.org>
Tested-by: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@chromium.org>
Reviewed-by: Jett Rink <9d4aef0593e6843318d99df31597fb6153b89787@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec