ACPI: buffer array too short in drivers/acpi/system.c

Since "ff_gbl_lock" has a length of 11 chars and is copied with sprintf
to char buffer[10], there is a problem. We need char buffer[12] because
of the closing zero byte.

Signed-off-by: Johann Felix Soden <johfel@users.sourceforge.net>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/system.c b/drivers/acpi/system.c
index 55cf4c0..4749f37 100644
--- a/drivers/acpi/system.c
+++ b/drivers/acpi/system.c
@@ -319,7 +319,7 @@
 		goto fail;
 
 	for (i = 0; i < num_counters; ++i) {
-		char buffer[10];
+		char buffer[12];
 		char *name;
 
 		if (i < num_gpes)