sys/amd64/conf/LINT-NOINET{6,}: don't set WITHOUT_INET{6,}_SUPPORT

Previously, it was necessary to set WITHOUT_INET_SUPPORT when building
the kernel without INET, and WITHOUT_INET6_SUPPORT when building the
kernel without INET6, or else the modules build would fail. The
LINT-NOINET and LINT-NOINET6 configs did this using makeoptions.

After recent changes, this is no longer required, so remove these
makeoptions. This avoids masking potential future build issues when
these aren't set.

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/1255

sys: Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Create in-tree LINT files

Now that config(8) has supported include for 19 years, transition to
including the NOTES files. include support didn't exist at the time,
nor did the envvar stuff recently added. Now that it does, eliminate
the building of LINT files by just including everything you need.

Note: This may cause conflicts with updating in some cases.
find sys -name LINT\* -rm
is suggested across this commit to remove the generated LINT
files.

Reviewed by: kevans
Differential Revision: https://reviews.freebsd.org/D26540