ACPI: Add ACPI_Q_AEI_NOPULL quirk and use in EC2

[cperciva]

Summary

AWS Graviton [1234] systems have a bug in their ACPI where they mark
the PL061's GPIO pins as needing to be configured in PullUp mode (in
fact the PL061 has no pullup/pulldown resistors); this flag needs to
be removed in order for _AEI objects to be handled on these systems.

Sponsored by: Amazon

[cperciva]

This patch doesn't actually use the flag but it will be handled in forthcoming changes to sys/dev/gpio/acpi_gpiobus.c as part of adding _AEI object support.

[cperciva]

Ali isn't able to get into Phabricator right now (possibly due to email issues between FreeBSD.org and Amazon.com) but out of band he said that this looked good to him.