mm: use pgdat_end_pfn() to simplify the code in arch

Use "pgdat_end_pfn()" instead of "pgdat->node_start_pfn +
pgdat->node_spanned_pages".  Simplify the code, no functional change.
Signed-off-by: NXishi Qiu <qiuxishi@huawei.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

arch/ia64/mm/init.c

@@ -357,9 +357,7 @@ int vmemmap_find_next_valid_pfn(int node, int i)
 
 	end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
 	end_address = PAGE_ALIGN(end_address);
-
-	stop_address = (unsigned long) &vmem_map[
-		pgdat->node_start_pfn + pgdat->node_spanned_pages];
+	stop_address = (unsigned long) &vmem_map[pgdat_end_pfn(pgdat)];
 
 	do {
 		pgd_t *pgd;

arch/metag/mm/init.c

@@ -148,7 +148,7 @@ static void __init bootmem_init_one_node(unsigned int nid)
 	if (!p->node_spanned_pages)
 		return;
 
-	end_pfn = p->node_start_pfn + p->node_spanned_pages;
+	end_pfn = pgdat_end_pfn(p);
 #ifdef CONFIG_HIGHMEM
 	if (end_pfn > max_low_pfn)
 		end_pfn = max_low_pfn;

arch/powerpc/mm/numa.c

@@ -938,8 +938,7 @@ static void __init mark_reserved_regions_for_nid(int nid)
 		unsigned long start_pfn = physbase >> PAGE_SHIFT;
 		unsigned long end_pfn = PFN_UP(physbase + size);
 		struct node_active_region node_ar;
-		unsigned long node_end_pfn = node->node_start_pfn +
-					     node->node_spanned_pages;
+		unsigned long node_end_pfn = pgdat_end_pfn(node);
 
 		/*
 		 * Check to make sure that this memblock.reserved area is

arch/sh/mm/init.c

@@ -231,7 +231,7 @@ static void __init bootmem_init_one_node(unsigned int nid)
 	if (!p->node_spanned_pages)
 		return;
 
-	end_pfn = p->node_start_pfn + p->node_spanned_pages;
+	end_pfn = pgdat_end_pfn(p);
 
 	total_pages = bootmem_bootmap_pages(p->node_spanned_pages);