bnxt: Fix driver when attached to a VF

• Use HWRM_FUNC_VF_CFG instead of HWRM_FUNC_CFG on VFs
• Fix NPAR/VF detection
• Clean up flag definitions
• Don't allow WoL on VFs

Although the bnxt driver doesn't support SR-IOV so can create VFs yet,
the PF could be running Linux or ESCi with a VF passed through to a
FreeBSD guest. This fixes the driver for that use case.

Submitted by: Siva Kallam <siva.kallam@@broadcom.com>
Reviewed by: shurd, sbruno
Approved by: sbruno (mentor)
Sponsored by: Broadcom Limited
Differential Revision: https://reviews.freebsd.org/D12410