tests: lib: ring_buffer: Increase timeot
tests: lib: ring_buffer: Increase timeot

The tests from tests/lib/ringbuffer fails on all nrf platforms due
to a timeout. Increasing the timeout value solves the issue.

Signed-off-by: Maciej Perkowski <cb34e965b6a5a3425eafdbd0feb7e469ae1417ea@nordicsemi.no>

galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr