x86/intel_rdt/cqm: Make integer rmid_limbo_count static

rmid_limbo_count is local to the source and does not need to be in global
scope, so make it static.

Cleans up sparse warning:
symbol 'rmid_limbo_count' was not declared. Should it be static?
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: kernel-janitors@vger.kernel.org
Link: https://lkml.kernel.org/r/20171002145931.27479-1-colin.king@canonical.com

arch/x86/kernel/cpu/intel_rdt_monitor.c

@@ -51,7 +51,7 @@ static LIST_HEAD(rmid_free_lru);
  *     may have a occupancy value > intel_cqm_threshold. User can change
  *     the threshold occupancy value.
  */
-unsigned int rmid_limbo_count;
+static unsigned int rmid_limbo_count;
 
 /**
  * @rmid_entry - The entry in the limbo and free lists.