IB/ipath: Fix problem with next WQE after a UC completion

This patch fixes a bug introduced when moving some code around for
readability.

Setting the wqe pointer at the end of the function is a NOP since it
isn't used.  Move it back to where it is used.

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