IB/qib: Fix txselect regression

commit 2fadd83184d58701f1116ca578465b5a75f9417c upstream.

Commit 7fac3301("IB/qib: checkpatch fixes") was overzealous in
removing a simple_strtoul for a parse routine, setup_txselect().  That
routine is required to handle a multi-value string.

Unwind that aspect of the fix.

Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>