[Keyboard] Refactor of onekey to support multiple development boards (#6017)

* Initial refactor of onekey to support multiple development boards

* Fixes to get teensy lc && 3.2 working

* Add pin tables

* Add caveats to Teensy boards

* Correct bootloader for Elite-C

keyboards/handwired/onekey/teensy_32/rules.mk

@@ -0,0 +1,41 @@
+## chip/board settings
+# - the next two should match the directories in
+#   <chibios>/os/hal/ports/$(MCU_FAMILY)/$(MCU_SERIES)
+# - For Teensies, FAMILY = KINETIS and SERIES is either
+#   KL2x (LC) or K20x (3.0,3.1,3.2).
+MCU_FAMILY = KINETIS
+MCU_SERIES = K20x
+
+# Linker script to use
+# - it should exist either in <chibios>/os/common/ports/ARMCMx/compilers/GCC/ld/
+#   or <this_dir>/ld/
+# - NOTE: a custom ld script is needed for EEPROM on Teensy LC
+# - LDSCRIPT =
+#   - MKL26Z64 for Teensy LC
+#   - MK20DX128 for Teensy 3.0
+#   - MK20DX256 for Teensy 3.1 and 3.2
+MCU_LDSCRIPT = MK20DX256
+
+# Startup code to use
+#  - it should exist in <chibios>/os/common/ports/ARMCMx/compilers/GCC/mk/
+# - STARTUP =
+#   - kl2x for Teensy LC
+#   - k20x5 for Teensy 3.0
+#   - k20x7 for Teensy 3.1 and 3.2
+MCU_STARTUP = k20x7
+
+# Board: it should exist either in <chibios>/os/hal/boards/
+#  or <this_dir>/boards
+# - BOARD =
+#   - PJRC_TEENSY_LC for Teensy LC
+#   - PJRC_TEENSY_3 for Teensy 3.0
+#   - PJRC_TEENSY_3_1 for Teensy 3.1 or 3.2
+BOARD = PJRC_TEENSY_3_1
+
+# Cortex version
+# Teensy LC is cortex-m0plus; Teensy 3.x are cortex-m4
+MCU  = cortex-m4
+
+# ARM version, CORTEX-M0/M1 are 6, CORTEX-M3/M4/M7 are 7
+# I.e. 6 for Teensy LC; 7 for Teensy 3.x
+ARMV = 7