IB/qib: Fix multi-Florida HCA host panic on reboot

Add check when setting configured contexts that the value does not
exceed the number of contexts allocated for the card.  If the value
exceeds the already allocated count, set it to what is already
allocated.

Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>