reef: Check PD reset level in tcpc_get_alert_status
reef: Check PD reset level in tcpc_get_alert_status

Only report alert status if the PD chip is not being held in reset.

(idea borrowed from Amenia's implementation)

BUG=none
BRANCH=none
TEST=built and booted on reef

Change-Id: Ic637b1ab4e20527c806311a45c149b9ea5f64362
Signed-off-by: David Hendricks <3b0deacc4b5357f519084f1ea34bd42bf5d34545@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/360020
Reviewed-by: Martin Roth <79230511ccf79da3f7e9e82dbcc9c1ec2f734fa0@chromium.org>

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