memblock: Kill early_node_map[]

Now all ARCH_POPULATES_NODE_MAP archs select HAVE_MEBLOCK_NODE_MAP -
there's no user of early_node_map[] left.  Kill early_node_map[] and
replace ARCH_POPULATES_NODE_MAP with HAVE_MEMBLOCK_NODE_MAP.  Also,
relocate for_each_mem_pfn_range() and helper from mm.h to memblock.h
as page_alloc.c would no longer host an alternative implementation.

This change is ultimately one to one mapping and shouldn't cause any
observable difference; however, after the recent changes, there are
some functions which now would fit memblock.c better than page_alloc.c
and dependency on HAVE_MEMBLOCK_NODE_MAP instead of HAVE_MEMBLOCK
doesn't make much sense on some of them.  Further cleanups for
functions inside HAVE_MEMBLOCK_NODE_MAP in mm.h would be nice.

-v2: Fix compile bug introduced by mis-spelling
 CONFIG_HAVE_MEMBLOCK_NODE_MAP to CONFIG_MEMBLOCK_HAVE_NODE_MAP in
 mmzone.h.  Reported by Stephen Rothwell.

Signed-off-by: Tejun Heo <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Yinghai Lu <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Chen Liqin <[email protected]>
Cc: Paul Mundt <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>

mm/memblock.c

@@ -716,7 +716,7 @@ phys_addr_t __init memblock_alloc(phys_addr_t size, phys_addr_t align)
 static phys_addr_t __init memblock_nid_range_rev(phys_addr_t start,
 						 phys_addr_t end, int *nid)
 {
-#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
+#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 	unsigned long start_pfn, end_pfn;
 	int i;