IB/ipath: Fix SM trap forwarding

SM/SMA traps received by the ipath driver should be forwarded to the
SM if it is running on the host.  The ib_ipath driver was incorrectly
replying with "bad method."

Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>