soc: arm: nordic nrf: use bitmode-16 for timing measurements in nrf51

nRF51 TIMER2 periperhal does not have the 32-bit
bitmode, so we need to fallback to the bitmode 16.

Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
1 file changed