RDMA/siw: Fix pointer-to-int-cast warning in siw_rx_pbl()

The variable buf_addr is type dma_addr_t, which may not be the same size
as a pointer.  To ensure it is the correct size, cast to a uintptr_t.

Fixes: c536277e0d ("RDMA/siw: Fix 64/32bit pointer inconsistency")
Link: https://lore.kernel.org/r/20200610174717.15932-1-tseewald@gmail.com
Signed-off-by: Tom Seewald <tseewald@gmail.com>
Reviewed-by: Bernard Metzler <bmt@zurich.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/sw/siw/siw_qp_rx.c

@@ -139,7 +139,8 @@ static int siw_rx_pbl(struct siw_rx_stream *srx, int *pbl_idx,
 			break;
 
 		bytes = min(bytes, len);
-		if (siw_rx_kva(srx, (void *)buf_addr, bytes) == bytes) {
+		if (siw_rx_kva(srx, (void *)(uintptr_t)buf_addr, bytes) ==
+		    bytes) {
 			copied += bytes;
 			offset += bytes;
 			len -= bytes;