Add io memory for classic parts

[stefanrueger]

This completes the io definition of memories.

[MCUdude]

Looks good to me! As you wrote in the docs, the io memory for classic parts is of limited use, since we can access these through a bootloader (Urboot compiled with IO register access perhaps?). But at least, now the io memory section is present!

[mcuee]

@stefanrueger

I am not so sure if the following test results are correct or not. It seems to me both usbasp programmer and urboot bootloader can not read the I/O memory of ATmega328P.

-c dryrun works fine.

PS C:\work\avr\avrdude_test\avrdude_bin> .\avrdude_pr1488 -C .\avrdude_pr1488.conf -c usbasp -p m328p -qqt
avrdude> dump io 0 0x10
avrdude_pr1488 error: (dump) error reading io address 0x00000 of part ATmega328P
                      read operation not supported on memory type io
avrdude> quit

PS C:\work\avr\avrdude_test\avrdude_bin> .\avrdude_pr1488 -C .\avrdude_pr1488.conf -c urclock -P COM40 -p m328p -xshowall
avrdude_pr1488: AVR device initialized and ready to accept instructions
0000ffffffff 2022-06-10 21.21 Blink.ino.standard.hex 924 store 31298 meta 34 boot 512 u7.7 weu-hprac vector 0 (RESET) ATmega328P

PS C:\work\avr\avrdude_test\avrdude_bin> .\avrdude_pr1488 -C .\avrdude_pr1488.conf -c urclock -P COM40 -p m328p -qqt
avrdude> dump io 0 0x10
avrdude_pr1488 error: bootloader cannot read from io
avrdude_pr1488 error: (dump) error reading io address 0x00000 of part ATmega328P
                      read operation not supported on memory type io
avrdude> quit

PS C:\work\avr\avrdude_test\avrdude_bin> .\avrdude_pr1488 -C .\avrdude_pr1488.conf -c dryrun -p m328p -qqt
avrdude> dump io 0 0x10
0000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
avrdude> write io 0 0xaa 0x55 0xaa 0x55
avrdude> dump io 0 0x10
0000  aa 55 aa 55 00 00 00 00  00 00 00 00 00 00 00 00  |.U.U............|
avrdude> quit

[stefanrueger]

not so sure if the following test results are correct

They are. io memory of classic parts has no current use as it cannot be externally accessed, and even internal access through a bootloader is only a theoretic possibility as no bootloader known to me supports this. So only interesting for future use, if any. This PR only makes sure all io memories are correctly described should some extension want to use it.