Now that ldconfig may get installed from a feed, use it when it's
available on the target.
(From OE-Core rev: 0f09f19dc48edf2ac50b554c18c217b7f97d4ae3)
Signed-off-by: Andreas Oberritter <obi@opendreambox.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>