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: Xishi Qiu <[e-mail]>
Cc: James Hogan <[e-mail]>
Cc: "Luck, Tony" <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Paul Mundt <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/ia64/mm/init.c

···
 
 	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

···
 	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

···
 		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

···
 	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);