RDMA/qedr: Fix and simplify memory leak in PD alloc

Free the PD if no internal resources were available. Move userspace
code under the relevant 'if'.

Signed-off-by: Ram Amrani <Ram.Amrani@cavium.com>
Signed-off-by: Ariel Elior <Ariel.Elior@cavium.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>