Input: add Imagis touchscreen driver

Add support for the IST3038C touchscreen IC from Imagis, based on
downstream driver. The driver supports multi-touch (10 touch points)
The IST3038C IC supports touch keys, but the support isn't added
because the touch screen used for testing doesn't utilize touch keys.
Looking at the downstream driver, it is possible to add support
for other Imagis ICs of IST30**C series.

Reviewed-by: Jeff LaBundy <jeff@labundy.com>
Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
Link: https://lore.kernel.org/r/20220305165330.13061-3-markuss.broks@gmail.com


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>