drivers: i2c: nios2: const driver config
drivers: i2c: nios2: const driver config

Moves the nios2 msgdma driver device config struct to the device data
struct for mutable data. The config struct is expected to be const.

Signed-off-by: Tom Burdick <63c280986e32082c9e27a1a69ac8b19e3d0c6b4b@intel.com>

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