x86: check boundary in setup_node_bootmem()

Commit dc098551 ("x86/uv: fix init of memory-less nodes") causes a
two sockets system (where node-1 doesn't have RAM installed) to crash.

That commit makes node_possible include cpu nodes that do not have memory.
So check boundary in setup_node_bootmem().

[ Impact: fix boot crash on RAM-less NUMA node system ]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Jack Steiner <steiner@sgi.com>
LKML-Reference: <49EF89DF.9090404@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/mm/numa_64.c

@@ -188,6 +188,9 @@ void __init setup_node_bootmem(int nodeid, unsigned long start,
 	const int pgdat_size = roundup(sizeof(pg_data_t), PAGE_SIZE);
 	int nid;
 
+	if (!end)
+		return;
+
 	start = roundup(start, ZONE_ALIGN);
 
 	printk(KERN_INFO "Bootmem setup node %d %016lx-%016lx\n", nodeid,