This patch is a no-op change that uses typedefs starting with avr_ in order to
make clear that they are in the avr "namespace".  Old types were: struct
base_arch_s, struct arch_info_s, struct mcu_type_s.

avr-cross builds fine.

Ok to apply?


	* config/avr/avr-arch.h
	(struct base_arch_s): Use typedef avr_arch_t instead.
	(struct arch_info_s): Use typedef avr_arch_info_t instead.
	(struct mcu_type_s): Use typedef avr_mcu_t instead.
	* config/avr/avr.c: Same.
	* config/avr/avr-devices.c: Same.
	* config/avr/driver-avr.c: Same.
	* config/avr/gen-avr-mmcu-texi.c: Same.
	* config/avr/avr-mcus.def: Adjust comment.