input: it7258_ts_i2c: add DT parsing support for touch driver

Add device tree support for ITE Tech touch controller driver.

Change-Id: I2671b7c30b0f2ed1d7ad788f29b7f900a2a1cdcc
Signed-off-by: Shantanu Jain <shjain@codeaurora.org>
Signed-off-by: Abinaya P <abinayap@codeaurora.org>