Nowadays, both boards boot using the TF-A BL1/BL2 and SPL isn't used at
all. The property is not needed, remove it.
Signed-off-by: NMichael Walle <michael@walle.cc>
Reviewed-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: NPriyanka Jain <priyanka.jain@nxp.com>