net: stmmac: make in-band AN mode parsing is supported for non-DT

commit 955efcc977ffa4fbe8935740837e95e38f162c50 from
https://source.codeaurora.org/external/autobsps32/linux



Not all platform uses DT, so phylink_parse_mode() will skip in-band setup
of pl->supported and pl->link_config.advertising entirely. So, we add the
setting of ovr_an_inband flag to make it works for non-DT platform.

Issue: ALB-8243
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit e5e5b771)
Signed-off-by: Radu Pirea (NXP OSS) <radu-nicolae.pirea@oss.nxp.com>
Signed-off-by: Zhantao Tang <zhantao.tang@windriver.com>