boards/arduino_due: remove redundant I2C default kconfigs

Enabling individual I2C controller is done in the SoC kconfig defaults.
There is no need to do that in the board defaults.

Change-Id: I45a62d8bc96a5f42b3fd613f5890bcdf04c92032
Signed-off-by: Daniel Leung <daniel.leung@intel.com>