IB/mlx4: Create paravirt contexts for VFs when master IB driver initializes

When we have VFs and PFs on same host, the VFs are activated within
the mlx4_core module before the mlx4_ib kernel module is loaded.

When the mlx4_ib module initializes the PF (master), it now creates
MAD paravirtualization contexts for any VFs that already active.

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Roland Dreier <roland@purestorage.com>