[Keyboard] Planck: Layout Macro Refactor (#4402)

[Keyboard] Planck: Layout Macro Refactor (#4402)

* Planck: layout macro refactor

Unified layout macro names across AVR and ARM boards.

Currently certain layout macros are specific to either AVR or ARM when used in the QMK Configurator. If an AVR-specific macro is used for a Planck rev. 6, or an ARM-specific macro on a rev. 5 or earlier, the user receives a compile error.

* Update keyboards/planck/planck.h per @drashna

Changed KC_LAYOUT_ortho_4x12 alias to LAYOUT_kc_ortho_4x12.

Co-Authored-By: noroadsleft <18669334+noroadsleft@users.noreply.github.com>
* Add KC_KEYMAP alias for LAYOUT_kc macro

per @drashna
Update keyboards/planck/planck.h

Co-Authored-By: noroadsleft <18669334+noroadsleft@users.noreply.github.com>
* Fix LAYOUT_planck_1x2uC macro for Planck rev6

Thanks to drashna for testing.

* Fix inline comment regarding revisions

* Add specific info.json file for Planck rev6