Update aarch64-none-elf-gcc and slave ports to 8.4.0

This updates :
devel/aarch64-none-elf-gcc
devel/arm-none-eabi-gcc
devel/riscv32-unknown-elf-gcc
devel/riscv64-none-elf-gcc

For now keep a distinfo file for each ports, when we know taht
we can updated them all together we will remove it and use only
the master port distinfo file.