sgi-xp: replace cpu_to_node() with cpu_to_mem() to support memoryless node

sgi-xp: replace cpu_to_node() with cpu_to_mem() to support memoryless node

xpc_create_gru_mq_uv() allocates memory with __GFP_THISNODE flag set,
which may cause permanent memory allocation failure on memoryless node.
So replace cpu_to_node() with cpu_to_mem() to better support memoryless
node.  For node with memory, cpu_to_mem() is the same as cpu_to_node().

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>