Fix bnxt build in LINT

LINT includes bnxt_re driver. Adjust the path in files, add missing
files and add a new BNXT_C to build (which thinly wraps OFED version
with bnxt specicif stuff).

Sponsored by: Netflix
Fixes: acd884dec99a ("RDMA/bnxt_re: Add bnxt_re RoCE driver")