Bluetooth: Controller: nrf: Use HAL for DPPI configuration

The following changes have been done:
1.
HAL_SW_SWITCH_GROUP_TASK_DISABLE_PPI_REGISTER_TASK(index)
  = HAL_SW_SWITCH_GROUP_TASK_DISABLE_PPI_TASK(channel)
has been convered into
HAL_SW_SWITCH_GROUP_TASK_DISABLE_PPI_REGISTER_TASK(index, channel)

2.
HAL_SW_SWITCH_GROUP_TASK_ENABLE_PPI_REGISTER_TASK(index)
  = HAL_SW_SWITCH_GROUP_TASK_ENABLE_PPI_TASK
Which was only used in one place, has been replaced with the
equivalent HAL call

3.
HAL_SW_SWITCH_GROUP_TASK_ENABLE_PPI_REGISTER_TASK(index) = 0
was replaced with the HAL subscribe clear function
nrf_dppi_subscribe_clear(NRF_DPPIC,
   HAL_SW_DPPI_TASK_EN_FROM_IDX(SW_SWITCH_TIMER_TASK_GROUP(index)));

4.
NRF_DPPIC->SUBSCRIBE_CHG[group].EN/DIS = 0;
have been replaced with the equivalent HAL clear call

5.
NRF_DPPIC->TASKS_CHG[group].DIS = 1;
have been replaced with the equivalent hal task_trigger() call

6.
Manually setting the CHG registers, has been replaced with a
clear + add (because the hal does not have a set function yet)
So,
  NRF_DPPIC->CHG[group] = value
has been replaced with
  nrf_dppi_group_clear(NRF_DPPIC, group);
  nrf_dppi_channels_include_in_group(NRF_DPPIC, value, group);
(A set function has been requested from the HAL team)

Note: There is other direct registes writes to the dppi subscribe and CHG
registers in the coded phy parts which have not been changed yet.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>