RDS/IB: Remove ib_[header/data]_sge() functions

These functions were to cope with differently ordered
sg entries depending on RDS 3.0 or 3.1+. Now that
we've dropped 3.0 compatibility we no longer need them.

Also, modify usage sites for these to refer to sge[0] or [1]
directly. Reorder code to initialize header sgs first.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c
index a68a3a7..e9fe08a 100644
--- a/net/rds/ib_recv.c
+++ b/net/rds/ib_recv.c
@@ -95,15 +95,15 @@
 		recv->r_wr.sg_list = recv->r_sge;
 		recv->r_wr.num_sge = RDS_IB_RECV_SGE;
 
-		sge = rds_ib_data_sge(ic, recv->r_sge);
-		sge->addr = 0;
-		sge->length = RDS_FRAG_SIZE;
-		sge->lkey = ic->i_mr->lkey;
-
-		sge = rds_ib_header_sge(ic, recv->r_sge);
+		sge = &recv->r_sge[0];
 		sge->addr = ic->i_recv_hdrs_dma + (i * sizeof(struct rds_header));
 		sge->length = sizeof(struct rds_header);
 		sge->lkey = ic->i_mr->lkey;
+
+		sge = &recv->r_sge[1];
+		sge->addr = 0;
+		sge->length = RDS_FRAG_SIZE;
+		sge->lkey = ic->i_mr->lkey;
 	}
 }
 
@@ -190,14 +190,14 @@
 	recv->r_frag->f_offset = ic->i_frag.f_offset;
 	recv->r_frag->f_mapped = dma_addr;
 
-	sge = rds_ib_data_sge(ic, recv->r_sge);
-	sge->addr = dma_addr;
-	sge->length = RDS_FRAG_SIZE;
-
-	sge = rds_ib_header_sge(ic, recv->r_sge);
+	sge = &recv->r_sge[0];
 	sge->addr = ic->i_recv_hdrs_dma + (recv - ic->i_recvs) * sizeof(struct rds_header);
 	sge->length = sizeof(struct rds_header);
 
+	sge = &recv->r_sge[1];
+	sge->addr = dma_addr;
+	sge->length = RDS_FRAG_SIZE;
+
 	get_page(recv->r_frag->f_page);
 
 	if (ic->i_frag.f_offset < RDS_PAGE_LAST_OFF) {