Input: add Raydium I2C touchscreen driver

This adds support for Raydium I2C touch controllers compatible with
RM32380.

Signed-off-by: Jeffrey Lin <jeffrey.lin@rad-ic.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>