configs: ls1028a: Enable the Ethernet switch driver in defconfig

The switch driver for LS1028A Ethernet switch is now compiled in for
the NXP LS1028A reference design boards and for the Kontron SMARC-sAL28.

Signed-off-by: Alex Marginean <alexandru.marginean@nxp.com>
Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Michael Walle <michael@walle.cc>