* gcc.target/avr/mmcu: New folder for compile-tests with -mmcu=.
	* gcc.target/avr/mmcu/avr-mmcu.exp: New file.
	* gcc.target/avr/pr58545.c: Move to gcc.target/avr/mmcu.
	* gcc.target/avr/tiny-caller-save.c: Dito.
	* gcc.target/avr/tiny-memx.c: Dito.

From-SVN: r243840