net/bnxt: add HWRM VNIC alloc

net/bnxt: add HWRM VNIC alloc

This requires a group info array in struct bnxt, so add that, we can save
the max size from the func_qcap response, and alloc/free in init/uninit

New HWRM call:
bnxt_hwrm_vnic_alloc:
	Allocates a VNIC resource in the hardware.

Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Signed-off-by: Stephen Hurd <stephen.hurd@broadcom.com>
Reviewed-by: David Christensen <david.christensen@broadcom.com>