bce_vhci: fix duplicate endpoint queue registration, ratelimit failure logging

bce_vhci_endpoint_create() was registering both the IN and OUT
submission queues on every call, regardless of which direction
the endpoint actually needed.
The per-stage firmware registration failures weren't rate-limited,
so a stuck registration will spam the console.

Tested on:
MacBookPro15,2
Macmini8,1
MacBookPro15,3
MacBookPro16,2

Reviewed by: adrian
Differential Revision: https://reviews.freebsd.org/D58831