Input: edt-ft5x06 - make wakeup-source switchable

Input: edt-ft5x06 - make wakeup-source switchable

Since day one the touch controller acts as wakeup-source. This seems to
be wrong since the device supports deep-sleep mechanism [1] which
requires a reset to leave it. Also some designs won't use the
touchscreen as wakeup-source.

According discussion [2] we decided to break backward compatibility and
go the common way by using the 'wakeup-source' device-property.

[1] https://www.newhavendisplay.com/appnotes/datasheets/touchpanel/FT5x26.pdf
[2] https://patchwork.kernel.org/patch/11149037/

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>