ITE: drivers/i2c: add the API of get configuration
ITE: drivers/i2c: add the API of get configuration

This commit adds the API of get_config that will make test of
tests/drivers/i2c/i2c_api pass on it8xxx2_evb board.

Signed-off-by: Tim Lin <38846f7070d5770410e9ef8b439c72e7b53a72c5@ite.corp-partner.google.com>

galak/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr