[PATCH 2/2] mm/sparse: add common helper to mark all memblocks present

Presently the arches arm64, arm and sh have a function which loops through
each memblock and calls memory present. riscv will require a similar
function.

Introduce a common memblocks_present() function that can be used by
all the arches. Subsequent patches will cleanup the arches that
make use of this.

...

--- a/mm/sparse.c
+++ b/mm/sparse.c

@@ -239,6 +239,17 @@ void __init memory_present(int nid, unsigned long start, unsigned long end)
 	}
 }
 
+void __init memblocks_present(void)
+{
+	struct memblock_region *reg;
+
+	for_each_memblock(memory, reg) {
+		memory_present(memblock_get_region_node(reg),
+			       memblock_region_memory_base_pfn(reg),
+			       memblock_region_memory_end_pfn(reg));
+	}
+}
+