virtual mux:Check pd task before waiting on task event
virtual mux:Check pd task before waiting on task event

Booting with a DP/Thunderbolt/USB4 device, causes an assert. Hence,
moving the check just before waiting on task event

BUG=b:175806234
BRANCH=None
TEST=Able to enter into tbt on reboot

Signed-off-by: Ayushee Shah <5730d7ed61dc96fa04bcc2bc2e4ce32af5b2c19d@intel.com>
Change-Id: If7bfcad18a07bb2879da018847c1716a21ba5737
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2596426
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