[media] staging: atomisp: lm3554: fix sparse warnings(was not declared. Should it be static?)

Fix "symbol 'xxxxxxx' was not declared. Should it be static?" sparse warnings.
Signed-off-by: Chen Guanqiao <chen.chenchacha@foxmail.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/staging/media/atomisp/i2c/lm3554.c

@@ -497,7 +497,7 @@ static const struct v4l2_ctrl_ops ctrl_ops = {
 	.g_volatile_ctrl = lm3554_g_volatile_ctrl
 };
 
-struct v4l2_ctrl_config lm3554_controls[] = {
+static const struct v4l2_ctrl_config lm3554_controls[] = {
 	{
 	 .ops = &ctrl_ops,
 	 .id = V4L2_CID_FLASH_TIMEOUT,
@@ -825,7 +825,7 @@ static int lm3554_gpio_uninit(struct i2c_client *client)
 	return 0;
 }
 
-void *lm3554_platform_data_func(struct i2c_client *client)
+static void *lm3554_platform_data_func(struct i2c_client *client)
 {
 	static struct lm3554_platform_data platform_data;