Esp32 HAL - fixed i2s stream, added PWM to extended pins

[Ringel]

Description

Fixes I2S Stream in ESP32 HAL. Last code didn't fill up the DMA buffer completely, leaving last ~4 samples from older calculation when no more steps were needed. This could result in permanent motor drift if a step was in the last 4 samples.

To direct access the last 16bit of the extension bypassing the DMA a new define I2S_STEPPER_SPLIT_STREAM was introduced for using in pins.h

To handle the extended pins as PWM - a timer inside the HAL adds PWM features - as current Marlin doesn't handle CONTROLLER_FAN, E?_AUTO_FAN by FAN_SOFT_PWM
This also resolves conflicting hardware usage for PWM and servos.

Benefits

Working Stepper Motors via i2s extender.
Working PWM for Controller, E0,E.. FANS via i2s extender in split mode

[simon-jouet]

I already replied to @Ringel in simon-jouet/ESP32Controller#10.

I'm all for the changes to i2s.cpp because they add the constant i2s channel + fix the DMA stream but I think we should old fire on the changes to PWM/timer, ledc is superior to a timer when we can use it so we probably should enable the timer and do soft PWM only when ledc is not usable

[Ringel]

@simon-jouet as suggested i'm using ledc for internal pins and fire the timer on first non-internal PWM pin usage.