make mm/sparse.c: make a function static

This patch makes the needlessly global sparse_early_mem_map_alloc()
static.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/sparse.c

@@ -377,7 +377,7 @@ struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid)
 }
 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 
-struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
+static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
 {
 	struct page *map;
 	struct mem_section *ms = __nr_to_section(pnum);