rpcrdma: Use XA_FLAGS_ALLOC instead of XA_FLAGS_ALLOC1

Nit: The built-in xa_limit_32b range starts at 0, but
XA_FLAGS_ALLOC1 configures the xarray's allocator to start at 1.
Adopt the more conventional XA_FLAGS_ALLOC because there's no
mechanical reason to skip 0.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprtrdma/ib_client.c

@@ -111,7 +111,7 @@ static int rpcrdma_add_one(struct ib_device *device)
 		return -ENOMEM;
 
 	kref_init(&rd->rd_kref);
-	xa_init_flags(&rd->rd_xa, XA_FLAGS_ALLOC1);
+	xa_init_flags(&rd->rd_xa, XA_FLAGS_ALLOC);
 	rd->rd_device = device;
 	init_completion(&rd->rd_done);
 	ib_set_client_data(device, &rpcrdma_ib_client, rd);