tests: drivers: i2c: Add support i2c_api test for RA4, RA2

Add conf and overlay to run i2c_api test on: ek_ra4w1,
ek_ra4m2, ek_ra4m3, ek_ra2a1

Signed-off-by: Tri Nguyen <tri.nguyen.wj@bp.renesas.com>
Signed-off-by: Khoa Nguyen <khoa.nguyen.xh@renesas.com>