IB/ipath: Use faster put_tid_2 routine after initialization

At one time the ipath_minrev field was initialized prior to the
ipath_init_iba6120_funcs call, but that is no longer the case, so the
slower put_tid routine was always being used.

Signed-off-by: Dave Olson <dave.olson@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>