* Start porting to Teensy 4.1, also fix some compiler warnings in FSL HAL

* Add hardware init for Teensy, refactor phy drivers, rework IMX EMAC autonegotiate code

* Revert some testing changes

* Fix incorrect phy address used outside of low_level_init_successful()

* Ethernet operational!

* Turn off DEBUG_IMX_EMAC

* Style fixes

* Style again

* Bugfix: mbed_lib.json files in project source dir were not getting picked up

* Bugfix: CLion debug configurations not generated properly due to variables going out of scope

* Support Teensy OTP MAC address

* MIMXRT: Make ncache region non-cached again

* Oops, remove print

* Fix incorrect image length in header preventing boot

* Fix ncache region being located in SEMC even on boards without it

* Don't reserve RAM for ncache anymore

* Fix crash when activating BufferedSerial on Teensy D0 and D1.  Also fix incorrect daisy register mapping.

* Fix missing space in linker script

* Start on fixing incorrect MIMXRT clock frequency

* LPM working!

* Clean up LPM and clocking

* Add teensy model identifier

* Fix license headers

* Initial attempt at Teensy 4.0 support

* Hide internal target

* Fix some targets.json issues, add boot code for the MIMXRT1060_EVK.  It boots but tests aren't able to run properly yet.

* Disable LPTICKER on MIMXRT1060, fix pin names for newer dev kits

* Enable MIMXRT106x ethernet