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 <tj@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index c7b68f4..cd7606b 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -58,6 +58,26 @@
 int memblock_free(phys_addr_t base, phys_addr_t size);
 int memblock_reserve(phys_addr_t base, phys_addr_t size);
 
+#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
+void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn,
+			  unsigned long *out_end_pfn, int *out_nid);
+
+/**
+ * for_each_mem_pfn_range - early memory pfn range iterator
+ * @i: an integer used as loop variable
+ * @nid: node selector, %MAX_NUMNODES for all nodes
+ * @p_start: ptr to ulong for start pfn of the range, can be %NULL
+ * @p_end: ptr to ulong for end pfn of the range, can be %NULL
+ * @p_nid: ptr to int for nid of the range, can be %NULL
+ *
+ * Walks over configured memory ranges.  Available after early_node_map is
+ * populated.
+ */
+#define for_each_mem_pfn_range(i, nid, p_start, p_end, p_nid)		\
+	for (i = -1, __next_mem_pfn_range(&i, nid, p_start, p_end, p_nid); \
+	     i >= 0; __next_mem_pfn_range(&i, nid, p_start, p_end, p_nid))
+#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
+
 void __next_free_mem_range(u64 *idx, int nid, phys_addr_t *out_start,
 			   phys_addr_t *out_end, int *out_nid);
 
@@ -101,9 +121,6 @@
 }
 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
 
-/* The numa aware allocator is only available if
- * CONFIG_ARCH_POPULATES_NODE_MAP is set
- */
 phys_addr_t memblock_find_in_range_node(phys_addr_t start, phys_addr_t end,
 					phys_addr_t size, phys_addr_t align, int nid);
 phys_addr_t memblock_alloc_nid(phys_addr_t size, phys_addr_t align, int nid);