USB port status register can be used to decide if a particular port
was responsible for generating PME# resulting in device wake:
1. CSC bit is set and port is capable of waking on connect/disconnect
2. PLC bit is set and port is in resume state
BUG=b:37088992
TEST=Verified with wake on USB2.0 port 3, mosys shows:
19 | 2017-06-08 15:43:30 | Wake Source | PME - XHCI (USB 2.0 port) | 3
Change-Id: Ie4fa87393d8f096c4b3dca5f7a97f194cb065468
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/20122
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
ef08545bff