XHCI: clear warm and port reset

It seems we do not clear UPS_C_BH_PORT_RESET and UPS_C_PORT_RESET
conditions after warm or port reset. Add that code.

Obtained from: an old patch mainly debugging other problems
Reviewed by: hselasky
Differential Revision: https://reviews.freebsd.org/D35483

(cherry picked from commit 8f892e9bee33fda1e2a2efca4b3e8a1949264cac)