IB/ipath: Fix error path in QP creation

This patch fixes the code which frees the partially allocated QP
resources if there was an error while creating the QP. In particular,
the QPN wasn't deallocated and the QP wasn't removed from the hash
table.

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