Tidy up the comments for the ppc64 flat memory support and fix a currently
benign double call to memory_present() for the first memory block.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>

diffstat sparsemem-ppc64-tidy-flat-memory-comments-and-fix-benign-mempresent-call
---

diff -upN reference/arch/ppc64/mm/init.c current/arch/ppc64/mm/init.c
--- reference/arch/ppc64/mm/init.c
+++ current/arch/ppc64/mm/init.c
@@ -635,18 +635,19 @@ void __init do_init_bootmem(void)
 
 	max_pfn = max_low_pfn;
 
-	/* add all physical memory to the bootmem map. Also, find the first
-	 * presence of all LMBs*/
+	/* Add all physical memory to the bootmem map, mark each area
+	 * present.  The first block has already been marked present above.
+	 */
 	for (i=0; i < lmb.memory.cnt; i++) {
 		unsigned long physbase, size;
 
 		physbase = lmb.memory.region[i].physbase;
 		size = lmb.memory.region[i].size;
-		if (i) { /* already created mappings for first LMB */
+		if (i) {
 			start_pfn = physbase >> PAGE_SHIFT;
 			end_pfn = start_pfn + (size >> PAGE_SHIFT);
+			memory_present(0, start_pfn, end_pfn);
 		}
-		memory_present(0, start_pfn, end_pfn);
 		free_bootmem(physbase, size);
 	}