The B2 board has different IO pins here for these two pins

Saves power and prevents heating

todo:
analogInputToDigitalPin(p)
digitalPinHasPWM(p)

Fixed the Serial2 object to use the new correct pins, plus made Serial8 only valid for T4 B1 (not B2).

Also I defined IO pins for the six signals associated with the SD Card slot.

I have tested these both as IO pins and now as SPI2

Moved from my flexio_t4 library.
Libary was updated to see if already defined before it now defines it.

Code from :: https://community.nxp.com/thread/389002
Name the fault dump info
New weak to override :: HardFault_HandlerC()

Allow the user to call setTX with the one hardware pin, and hopefully allow them to turn on Open Drain mode or turn it back off.  I don't currently have any test cases that use this, so not sure how well it works.

Page 982.
Fixes https://forum.pjrc.com/threads/54711-Teensy-4-0-First-Beta-Test?p=196233&viewfull=1#post196233
- maybe this is needed for T3x, too? too late here to check this now.