xhci(4): Correct PCI device IDs for Zhaoxin USB 3.0 controllers

And minor style fixes.

Reviewed by: hselasky
Tested by: Weitao Wang <WeitaoWang-oc@zhaoxin.com>
Fixes: 0d7064d58f89 xhci(4): Add new USB IDs
Differential Revision: https://reviews.freebsd.org/D38921