memblock: let memblock_type_name know about physmem type

Since commit 70210ed950b5 ("mm/memblock: add physical memory list") the
memblock structure knows about a physical memory list.

memblock_type_name() should return "physmem" instead of "unknown" if the
name of the physmem memblock_type is being asked for.

Link: http://lkml.kernel.org/r/20170120123456.46508-2-heiko.carstens@de.ibm.com
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memblock.c

@@ -72,6 +72,10 @@ memblock_type_name(struct memblock_type *type)
 		return "memory";
 	else if (type == &memblock.reserved)
 		return "reserved";
+#ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
+	else if (type == &memblock.physmem)
+		return "physmem";
+#endif
 	else
 		return "unknown";
 }