net: dpaa2: use pcs-lynx's check for fwnode availability

commit  901e63daf90cb3435b42370716ed23c135a38b03 from
https://github.com/nxp-imx/linux-imx lf-6.1.y

Use pcs-lynx's check rather than our own when determining if the device
is available.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
(cherry picked from commit 8c1d0b33

)
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>