pcnt_del_channel() function

PCNT channel handle created by `pcnt_new_channel()`

Create PCNT channel for specific unit, each PCNT has several channels associated with it

Set channel actions when edge signal changes (e.g. falling or rising edge occurred). The edge signal is input from the `edge_gpio_num` configured in `pcnt_chan_config_t`. We use these actions to control when and how to change the counter value.

Set channel actions when level signal changes (e.g. signal level goes from high to low). The level signal is input from the `level_gpio_num` configured in `pcnt_chan_config_t`. We use these actions to control when and how to change the counting mode.