Fix other warnings

Most were harmless, but the change to ACCESS_ONCE from volatile
cast is probably useful.
Expanding macro, we basically went from:
    m = (volatile struct sdma_vl_map *)dd->sdma_map;
to
    m = *(volatile struct sdma_vl_map **)&(dd->sdma_map);
i.e. the explicit lookup is at a different level.

kernel/include/hfi1/sdma.h

@@ -764,8 +764,8 @@ static inline int sdma_txadd_page(
 	u16 len)
 {
 	dma_addr_t addr;
-	int rval;
 #ifdef __HFI1_ORIG__
+	int rval;
 	/* TODO: check this coealesce thing */
 	hfi1_cdbg(AIOWRITE, "+");
 	if ((unlikely(tx->num_desc == tx->desc_limit))) {