powerpc/mm: Mark Memory Resources as busy

Memory I/O resources need to be marked as busy or else we cannot remove
them when doing memory hot remove.

Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/mm/mem.c

@@ -514,7 +514,7 @@ static int add_system_ram_resources(void)
 			res->name = "System RAM";
 			res->start = base;
 			res->end = base + size - 1;
-			res->flags = IORESOURCE_MEM;
+			res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 			WARN_ON(request_resource(&iomem_resource, res) < 0);
 		}
 	}