Merge remote-tracking branch 'remotes/philmd/tags/avr-20210315' into staging

Merge remote-tracking branch 'remotes/philmd/tags/avr-20210315' into staging

AVR patches queue

- Only reset 'interrupt_request' mask once all interrupts executed
- Documentation and typo fixes

# gpg: Signature made Sun 14 Mar 2021 23:45:34 GMT
# gpg:                using RSA key FAABE75E12917221DCFD6BB2E3E32C2CDEADC0DE
# gpg: Good signature from "Philippe Mathieu-Daudé (F4BUG) <f4bug@amsat.org>" [full]
# Primary key fingerprint: FAAB E75E 1291 7221 DCFD  6BB2 E3E3 2C2C DEAD C0DE

* remotes/philmd/tags/avr-20210315:
  target/avr: Fix interrupt execution
  target/avr: Fix some comment spelling errors
  hw/avr/arduino: List board schematic links
  hw/misc/led: Add yellow LED

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>