usb/mux: Do not connect MUX when PD disconnected
usb/mux: Do not connect MUX when PD disconnected

When chipset power up to S5->S3 state set PD_EVENT_POWER_STATE_CHANGE,
pd task set mux usb mode whether c-port is attached or not.
If c-port is nothing attached at the setting moment,
then mux detects nothing and goes to low power state.
Plug-in type-c usb device, after debounce pass, we set mux usb
mode and mux responds i2C NAK (due to in low power mode).

This CL changes that do not connect MUX when PD disconnected.
For example ps8751 is used for mux case. When power up(S5->S3),
we should set mux none mode whether c-port is attached or not.
Once type-c usb device plug-in, after cc debounce pass, we
will set mux usb mode in X_DEBOUNCE_DISCONNECT state.

BRANCH=None
BUG=b:133196882
TEST=After console cmd reboot and reboot hard,
     type-c usb device plug-in on ampton and
     get type-c port status by "ectool usbpdmuxinfo".

Change-Id: Ia538af48c450e12af1438a6aa9a6e4e426e2f616
Signed-off-by: Ruibin Chang <6748d95250dd3d29f04d200035d5434f3b7820ef@ite.com.tw>
Reviewed-on: https://chromium-review.googlesource.com/1609262
Legacy-Commit-Queue: Commit Bot <5c2bf027dc5cc7ef186314391646e49f6866dc00@chromium.org>
Reviewed-by: Jett Rink <9d4aef0593e6843318d99df31597fb6153b89787@chromium.org>
Reviewed-by: Daisuke Nojiri <fd5f93af191bf7e8f73ea71cc3c0f66b41b1dd49@chromium.org>

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