boards: Add arduino_gpio & and arduino_i2c to board supported

Update a number of boards that have arduino_gpio and arduino_i2c
support in their dts files to show that they support that in the
board.yaml file.  This allows coverage on several shield tests that
utilize the tags 'arduino_gpio' and 'arduino_i2c'.

Exlucde stm32mp157c_dk2 from some of the samples right now since the
connector on the board doesn't support A2/A3.  Also remove the duplicate
of exluding disco_l475_iot1.

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>