Make sure to free the DSR on pvrdma_pci_remove() to avoid the memory leak.

Fixes: 29c8d9eb ("IB: Add vmw_pvrdma driver")
Signed-off-by: Kamal Heib <kamalheib1@gmail.com>
Acked-by: Adit Ranadive <aditr@vmware.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>