RDS: fold rdma.h into rds.h

RDMA is now an intrinsic part of RDS, so it's easier to just have
a single header.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index 5011efa..a21edad 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -35,7 +35,7 @@
 #include <linux/rbtree.h>
 #include <linux/dma-mapping.h> /* for DMA_*_DEVICE */
 
-#include "rdma.h"
+#include "rds.h"
 
 /*
  * XXX