Revert "Input: clear BTN_RIGHT/MIDDLE on buttonpads"

This reverts commit 37ef4c1.

The touchpad present in the Dell Precision 7550 and 7750 laptops
reports a HID_DG_BUTTONTYPE of type MT_BUTTONTYPE_CLICKPAD. However,
the device is not a clickpad, it is a touchpad with physical buttons.

In order to fix this issue, a quirk for the device was introduced in
libinput [1] [2] to disable the INPUT_PROP_BUTTONPAD property:

	[Precision 7x50 Touchpad]
	MatchBus=i2c
	MatchUdevType=touchpad
	MatchDMIModalias=dmi:*svnDellInc.:pnPrecision7?50*
	AttrInputPropDisable=INPUT_PROP_BUTTONPAD

However, because of the change introduced in 37ef4c1 ("Input: clear
BTN_RIGHT/MIDDLE on buttonpads") the BTN_RIGHT key bit is not mapped
anymore breaking the device right click button and making impossible to
workaround it in user space.

In order to avoid breakage on other present or future devices, revert
the patch causing the issue.

Signed-off-by: José Expósito <[email protected]>
Reviewed-by: Hans de Goede <[email protected]>
Acked-by: Peter Hutterer <[email protected]>
Acked-by: Benjamin Tissoires <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Dmitry Torokhov <[email protected]>

Author: JoseExposito

drivers/input/input.c

@@ -2337,12 +2337,6 @@ int input_register_device(struct input_dev *dev)
 	/* KEY_RESERVED is not supposed to be transmitted to userspace. */
 	__clear_bit(KEY_RESERVED, dev->keybit);
 
-	/* Buttonpads should not map BTN_RIGHT and/or BTN_MIDDLE. */
-	if (test_bit(INPUT_PROP_BUTTONPAD, dev->propbit)) {
-		__clear_bit(BTN_RIGHT, dev->keybit);
-		__clear_bit(BTN_MIDDLE, dev->keybit);
-	}
-
 	/* Make sure that bitmasks not mentioned in dev->evbit are clean. */
 	input_cleanse_bitmasks(dev);