board: ti: am65x: Add check for k3-am654-icssg2 in board_fit_config_match()

When CONFIG_TI_ICSSG_PRUETH is enabled, add config name check for the
icssg2 overlay in board_fit_config_match() API.

Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Acked-by: Ravi Gunasekaran <r-gunasekaran@ti.com>