Staging: iio: trigger: fix up some global variables

These should be static.

Cc: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/trigger/iio-trig-gpio.c

@@ -25,8 +25,8 @@
 #include "../iio.h"
 #include "../trigger.h"
 
-LIST_HEAD(iio_gpio_trigger_list);
-DEFINE_MUTEX(iio_gpio_trigger_list_lock);
+static LIST_HEAD(iio_gpio_trigger_list);
+static DEFINE_MUTEX(iio_gpio_trigger_list_lock);
 
 struct iio_gpio_trigger_info {
 	struct mutex in_use;

drivers/staging/iio/trigger/iio-trig-periodic-rtc.c

@@ -19,8 +19,8 @@
 #include "../iio.h"
 #include "../trigger.h"
 
-LIST_HEAD(iio_prtc_trigger_list);
-DEFINE_MUTEX(iio_prtc_trigger_list_lock);
+static LIST_HEAD(iio_prtc_trigger_list);
+static DEFINE_MUTEX(iio_prtc_trigger_list_lock);
 
 struct iio_prtc_trigger_info {
 	struct rtc_device *rtc;