Revert "usb: typec: ucsi: add a common function ucsi_unregister_connectors()"

In the Linux kernel, the following vulnerability has been resolved:

Revert "usb: typec: ucsi: add a common function ucsi_unregister_connectors()"

The recent commit 87d0e2f41b8c ("usb: typec: ucsi: add a common
function ucsi_unregister_connectors()") introduced a regression that
caused NULL dereference at reading the power supply sysfs. It's a
stale sysfs entry that should have been removed but remains with NULL
ops. The commit changed the error handling to skip the entries after
a NULL con->wq, and this leaves the power device unreleased.

For addressing the regression, the straight revert is applied here.
Further code improvements can be done from the scratch again.