IB/qib: Fix M_Key lease timeout handling

If a port has an M_Key lease set, the M_Key protect bits set to 1, and
a SubnSet arrives with an invalid M_Key, an M_Key mismatch trap is
generated, the lease timer begins as expected, and eventually the
M_Key protect bits will be set back to 0 as per the spec.  However, if
any other SMP with an invalid M_Key arrives, the lease timer is expired
and the M_Key protect bits remain in force.

This is not according to to spec.  In particular, C14-17 says that
a lease timer that is underway is not affected by protection level
checks (ie, at protection level 1, a SubnGet with a bad M_Key may be
successful, but does not stop the timer), and C14-19 says that the timer
shall stop when a valid M_Key has been received.  C14-19 is the only
compliance statement that specifies a stopping condition for the timer.

This behavior is magnified if the port's Master SM LID attribute
points at itself.  In that case, the M_Key mismatch trap is sufficient to
expire the timer, and the mkey lease attribute is rendered useless.

Reviewed-by: Ram Vepa <ram.vepa@qlogic.com>
Signed-off-by: Jim Foraker <foraker1@llnl.gov>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>