Add support for ATmega1284p

Add ATmega128RFA1 support

Adds basic ATmega128RFA1 support. Adjusts the common USART patches for
UCSZ? slightly to work with the ATmega128RFA1's ATDF.

Add support for ATtiny1614

Add support for ATtiny816

Add basic support for the ATtiny816 of the tinyAVR1-series.

Add support for ATtiny2313/A

Fix build with svd2rust 0.19

Upgrade to svd2rust version 0.19.  We can make use of the new --make_mod
option nicely.

Add ATtiny167 support

Add ATtiny202 support

All of the svd patches are in patch/common/attiny-0-series.yaml which should
work for all of the 0-series (but may only work for ATtiny20* and ATtiny40*,
  but not 80* or 160* given how the datasheet is split)

Add AT90USB1286 support

Ref: #80

Add ATmega8U2

Add attiny841 and attiny861

Replace gen-intr-lut.sh sed hack with svdtools

svdtools comes with a command to list all interrupts
from an SVD file.  Use this instead of fragile sed magic
which parses the generated rust code.

Add basic support for ATmega4809

Add support for atmega328pb

patch: Switch to upstream svdtools patch tool

Instead of using our locally vendored version of svdpatch, switch to the
upstream version maintained by the stm32-rs project:

    https://github.com/stm32-rs/svdtools

Signed-off-by: Rahix <rahix@rahix.de>

Add basic support for ATmega644

Add support for the ATtiny84

Add atmega48p device support

make: Properly remove 'extern crate' lines

The previous sed expression would remove arbitrary lines which can break
easily.  Instead, only remove actual extern crate lines.

This will provide a seamless upgrade to the next svd2rust version which
contains commit 85615cb0bbc8 ("Use and generate code for Edition 2018
only ") and thus no longer emits 'extern crate' lines.

Signed-off-by: Rahix <rahix@rahix.de>

Add basic support for ATmega168