IB/ipath: Drop support for the original QHT7040 board

The original QHT7040 had significant performance issues so there was an
additional check in the driver for a newer serial number.  Support for
the small quantities of that board shipped has been dropped, so this
patch removes the special checks to simplify the code.

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