RDMA: Handle PD allocations by IB/core

The PD allocations in IB/core allows us to simplify drivers and their
error flows in their .alloc_pd() paths. The changes in .alloc_pd() go hand
in had with relevant update in .dealloc_pd().

We will use this opportunity and convert .dealloc_pd() to don't fail, as
it was suggested a long time ago, failures are not happening as we have
never seen a WARN_ON print.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/sw/rdmavt/pd.h

@@ -50,9 +50,8 @@
 
 #include <rdma/rdma_vt.h>
 
-struct ib_pd *rvt_alloc_pd(struct ib_device *ibdev,
-			   struct ib_ucontext *context,
-			   struct ib_udata *udata);
-int rvt_dealloc_pd(struct ib_pd *ibpd);
+int rvt_alloc_pd(struct ib_pd *pd, struct ib_ucontext *context,
+		 struct ib_udata *udata);
+void rvt_dealloc_pd(struct ib_pd *ibpd);
 
 #endif          /* DEF_RDMAVTPD_H */