Remove other maintainers

Co-authored-by: Jubilee <[email protected]>

Author: knickish

src/doc/rustc/src/platform-support/m68k-unknown-none-elf.md

@@ -7,8 +7,6 @@ Bare metal Motorola 680x0
 ## Designated Developers
 
 * [@knickish](https://github.com/knickish)
-* [@glaubitz](https://github.com/glaubitz)
-* [@ricky26](https://github.com/ricky26)
 
 ## Requirements