x86/apic/vsmp: Make is_vsmp_box() static

Since checkin

411cf9ee x86, vsmp: Remove is_vsmp_box() from apic_is_clustered_box()

... is_vsmp_box() is only used in vsmp_64.c and does not have any
header file declaring it, so make it explicitly static.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: Shai Fultheim <shai@scalemp.com>
Cc: Oren Twaig <oren@scalemp.com>
Link: http://lkml.kernel.org/r/1404036068-11674-1-git-send-email-oren@scalemp.comSigned-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/vsmp_64.c

@@ -152,7 +152,7 @@ static void __init detect_vsmp_box(void)
 		is_vsmp = 1;
 }
 
-int is_vsmp_box(void)
+static int is_vsmp_box(void)
 {
 	if (is_vsmp != -1)
 		return is_vsmp;
@@ -166,7 +166,7 @@ int is_vsmp_box(void)
 static void __init detect_vsmp_box(void)
 {
 }
-int is_vsmp_box(void)
+static int is_vsmp_box(void)
 {
 	return 0;
 }