mlx4_core: Increase max number of QPs to 128K

With the advent large clusters which utilize multicore hosts, 64K QPs
is not enough.  We should increase the default maximum for QPs to 128K.

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