x86: reduce force_mwait visibility

It's not used anywhere outside its single referencing file.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 158bd6a..9f94bb1 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -199,6 +199,7 @@
  *
  * idle=mwait overrides this decision and forces the usage of mwait.
  */
+static int __cpuinitdata force_mwait;
 
 #define MWAIT_INFO			0x05
 #define MWAIT_ECX_EXTENDED_INFO		0x01