drivers: nrfx: Update implementations after switching to nrfx 2.0.0

Update calls to nrfx HAL functions to reflect API changes introduced in
nrfx 2.0.0. All these functions are now called with the first parameter
pointing to the structure of registers of the relevant peripheral.
Also a few functions got renamed:
- nrf_gpiote_int_is_enabled to nrf_gpiote_int_enable_check
- nrf_gpiote_event_is_set to nrf_gpiote_event_check
- nrf_rng_event_get to nrf_rng_event_check
- nrf_rng_int_get to nrf_rng_int_enable_check
- nrf_rtc_event_pending to nrf_rtc_event_check
- nrf_rtc_int_is_enabled to nrf_rtc_int_enable_check
- nrf_timer_cc_read to nrf_timer_cc_get
- nrf_timer_cc_write to nrf_timer_cc_set

Default configuration values were removed from nrfx_config files,
so the drivers pwm_nrfx and spi_nrfx_spis no longer can use those.

Function nrfx_pwm_init() now takes one more parameter - context pointer
that is passed to the event handler, not used in the pwm_nrfx driver.

HALs for UART and UARTE now allow configuration of the parity type
and the number of stop bits, for SoCs that provide the corresponding
registers.

Signed-off-by: Karol Lasończyk <karol.lasonczyk@nordicsemi.no>
Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>