The NRF52 define only covers nrf52832, so update the define checks
to use NRF52_SERIES to cover both nrf52832 and nrf52840.
Fixed machine_hard_pwm_instances table in modules/machine/pwm.c
This enables PWM(0) to PWM(3), RTCounter(2), Timer(3) and Timer(4),
in addition to NFC reset cause, on nrf52840.