HID: hiddev - fix compiler warning

drivers/hid/usbhid/hiddev.c: In function 'hiddev_compat_ioctl':
drivers/hid/usbhid/hiddev.c:746: warning: passing argument 4 of 'hiddev_ioctl' makes
integer from pointer without a cast

Add cast to hiddev_compat_ioctl()

Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/usbhid/hiddev.c

@@ -743,7 +743,7 @@ inval:
 static long hiddev_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = file->f_path.dentry->d_inode;
-	return hiddev_ioctl(inode, file, cmd, compat_ptr(arg));
+	return hiddev_ioctl(inode, file, cmd, (unsigned long)compat_ptr(arg));
 }
 #endif