generic: Fix up the v6.12 config for ARM

generic: Fix up the v6.12 config for ARM

This adds a few ARM-related kconfig options that makes the
configure phase smooth on ARM (32bit) systems.

We default PAN to enabled for protection, however this has
a syscall speed penalty, if your system is interacting a lot
from userspace you might want to disable it for speed vs
security. For in-kernel routing it should not be a major
issue.

Some marginal ARM system enables DRM so make sure we have
the related DRM Kconfigs set up to unselected.

Link: https://github.com/openwrt/openwrt/pull/18900
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>