Just for "fun" I've tried setting few other of mlx4_core params in /etc/modprobe.d/mlx4.conf: probe_vf, num_vfs, hpn, debug_level.
First 2 are undefined by default. Other two are both 0 by default.
options mlx4_core port_type_array=2,2 num_vfs=8,0,0 probe_vf=8,0,0 hpn=1 debug_level=6
Tried...