glibc: move ld.so.conf back to main package

There are cases where one doesn't want ldconfig on target (e.g. for
read-only root filesystems, it's rather pointless), yet one still
needs ld.so.conf to be present at image build time:

When some recipe installs libraries to a non-standard location, and
dutifully drops in a file in /etc/ld.so.conf.d/foo.conf, we need the
ld.so.conf containing the

  include /etc/ld.so.conf.d/*.conf

stanza to get those other locations picked up.

So change the packaging logic so that there's always an ld.so.conf
present when the build-time ldconfig runs.

The ld.so.conf and ld.so.conf.d/*.conf files don't take up much
room (at least not compared to the 700K binary ldconfig), and they
might be needed in case ldconfig is installable, so leave them
alone.

In case of a read-only rootfs, one could add some logic to remove them
if one really wants to shave those few dozens of bytes off.

While here, fix typos in the bb.note (add spaces) so one can just
copy-paste the line from the log-file and redo the command.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>