HID: vivaldi: Minor cleanups

Perform some minor cleanups on this driver. Include header files for
struct definitions that are used, drop a forward declaration that isn't
useful, and mark a sysfs attribute static as it isn't used outside this
file.

Cc: Sean O'Brien <seobrien@chromium.org>
Cc: Ting Shen <phoenixshen@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Author: bebarino

drivers/hid/hid-vivaldi.c

@@ -6,16 +6,17 @@
  * Author: Sean O'Brien <seobrien@chromium.org>
  */
 
+#include <linux/device.h>
 #include <linux/hid.h>
+#include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/sysfs.h>
 
 #define MIN_FN_ROW_KEY	1
 #define MAX_FN_ROW_KEY	24
 #define HID_VD_FN_ROW_PHYSMAP 0x00000001
 #define HID_USAGE_FN_ROW_PHYSMAP (HID_UP_GOOGLEVENDOR | HID_VD_FN_ROW_PHYSMAP)
 
-static struct hid_driver hid_vivaldi;
-
 struct vivaldi_data {
 	u32 function_row_physmap[MAX_FN_ROW_KEY - MIN_FN_ROW_KEY + 1];
 	int max_function_row_key;
@@ -40,7 +41,7 @@ static ssize_t function_row_physmap_show(struct device *dev,
 	return size;
 }
 
-DEVICE_ATTR_RO(function_row_physmap);
+static DEVICE_ATTR_RO(function_row_physmap);
 static struct attribute *sysfs_attrs[] = {
 	&dev_attr_function_row_physmap.attr,
 	NULL