Input: tca6416-keypad - remove unused struct tca6416_drv_data

"struct tca6416_drv_data" is unused.
Remove it.

Found with cppcheck, unusedStructMember.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/3e6fd1d0875ef3c90ecaab7adf7fd4a5e8e6f708.1714541432.git.christophe.jaillet@wanadoo.frSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/tca6416-keypad.c

@@ -32,11 +32,6 @@ static const struct i2c_device_id tca6416_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, tca6416_id);
 
-struct tca6416_drv_data {
-	struct input_dev *input;
-	struct tca6416_button data[];
-};
-
 struct tca6416_keypad_chip {
 	uint16_t reg_output;
 	uint16_t reg_direction;