RDMA/nes: Limit critical error interrupts

Mask off a critical error after 100 critical error interrupts to
keep the system "sane".

Signed-off-by: Sweta Bhatt <sweta.bhatt@einfochips.com>
Signed-off-by: Chien Tung <ctung@neteffect.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>