driver: net: fsl-mc: Fix DPC MAC address fixup

driver: net: fsl-mc: Fix DPC MAC address fixup

If node /board_info/ports does not exist in the DPC file,
function mc_fixup_dpc() will skip not only MAC address fixup,
but also the cache flush at the end. This may cause the other
fixup changes (e.g. ICID related ones) to be ignored by MC.

Fixes: 1161dbcc0a36 ("drivers: net: fsl-mc: Include MAC addr fixup to DPL")
Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>