Let's switch the driver to using threaded IRQ so that we do not need to
manage the interrupt and work separately, and we do not acknowledge
interrupt until we finished handling it completely.
Tested-by: Adam Ford <aford173@gmail.com> #imx6q-logicpd Tested-by: Sven Van Asbroeck <TheSven73@gmail.com> # ILI2118A variant Tested-by: Marek Vasut <marex@denx.de> # ILI2117 Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>