Avoid fast pins IO on RTOS based boards

[facchinm]

Better fix than arduino/ArduinoCore-zephyr@80943e6

@KurtE

Once we are touching this file, I'd also take a look at why UNO R4 is not in the FAST_IO path (see d5aa1a3#r150329231 )

[KurtE]

@facchinm - Would be good if it could be in the fast io...

At one point I was going to do so. I do have for example my own digitalWriteFast and the like calls, As do several others up on the forum, which work a lot faster than standard ones.

Would be reasonably easy to setup something within BUSIO... Which either uses the similar table that is I believe marked private or like I did:

static R_PORT0_Type * const port_table[] = { R_PORT0, R_PORT1, R_PORT2, R_PORT3, R_PORT4, R_PORT5, R_PORT6, R_PORT7 };
static const uint16_t mask_table[] = { 1 << 0, 1 << 1, 1 << 2, 1 << 3, 1 << 4, 1 << 5, 1 << 6, 1 << 7,
                                       1 << 8, 1 << 9, 1 << 10, 1 << 11, 1 << 12, 1 << 13, 1 << 14, 1 << 15 };
// quick and dirty digitalWriteFast
static inline void digitalWriteFast(pin_size_t pin, PinStatus val) {
  uint16_t hardware_port_pin = g_pin_cfg[pin].pin;
  //uint16_t mask = 1 << (hardware_port_pin & 0xf);
  uint16_t pin_mask = mask_table[hardware_port_pin & 0xf];
  R_PORT0_Type * const portX = port_table[hardware_port_pin >> 8];

  if (val) portX->POSR = pin_mask;
  else portX->PORR = pin_mask;
}

Obviously, one could then have the BUSIO code either hold onto the Port or the SET and Clear registers
and the mask... Which is probably similar to what we did for Teensy 4.x which likewise have the Set and Clear
registers... On T3.x we used the BIT band address, which I found out was optional on M4 boards and not on the R4...

I took the easy route to get these boards working on the libraries that used BUSIO as there was pushback on forum about
adding things like this....

But I hope you do!

[ladyada]

thanks for the fix, apologies for the delay!