Input: edt_ft5x06 - use devm_* functions where appropriate

Simplify the error path and remove() function by using devm_*
functions for requesting gpios and irq and allocating the input
device.

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>