virtual mux: Wait for mux config ACK from AP on disconnect
virtual mux: Wait for mux config ACK from AP on disconnect

While switching from DP to Thunderbolt mode, EC sends a mux disconnect
followed by a USB mux connect. Since these events are one behind the
other, AP might miss the disconnect mux event. Hence, this CL waits for
an ACK from AP, to synchronize the disconnect mux event between AP and
EC.

BUG=b:186609339
BRANCH=None
TEST=1.Both the monitors behind the Tortilla based dock enumerate after
       coldboot.
     2.Checked Disconnect-Connect with TBT/USB4 device in S0ix, they
       enumerate fine on full resume.
     3.Checked coldboot with non-Tortilla based dock based dock. it
       enumerates fine.

Signed-off-by: Ayushee Shah <5730d7ed61dc96fa04bcc2bc2e4ce32af5b2c19d@intel.com>
Change-Id: Ib32c3426c2b52b1af582729453d748902447900c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2857374
Reviewed-by: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>

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