tests: drivers: counter: pic32cx_sg61_cult: Adds test support files

- Adds pic32cx_sg61_cult.overlay file for rtc.
- Adds an extra scenario to testcase.yaml in counter basic api
- Updates the sam_e54_xpro scenario in testcase.yaml

Signed-off-by: Farsin Nasar V A <farsin.nasarva@microchip.com>
Signed-off-by: Muhammed Asif <muhammed.asif@microchip.com>