tests: drivers: pwm: Add support test pwm for RA4E1 boards

- Add overlay to support test app pwm_api for voice_ra4e1
- Add support test app pwm_loopback for fpb_ra4e1 and
voice_ra4e1 boards

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