IB/ipath: Better handling of unexpected GPIO interrupts

The General Purpose I/O pins can be configured to cause interrupts. At
the end of the interrupt code dealing with all known causes, a message
is output if any bits remain un-handled. Since this is a "can't happen"
scenario, it should only be triggered by bugs elsewhere. It is harmless,
and potentially beneficial, to limit the damage by masking any such
unexpected interrupts.

This patch adds disabling of interrupts from any pins that should
not have been allowed to interrupt, in addition to emitting a message.

Signed-off-by: Michael Albaugh <Michael.Albaugh@Qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>