xilinx: common: Optimise updating ethaddr from eeprom

xilinx: common: Optimise updating ethaddr from eeprom

In board_late_init_xilinx() eth*addr are updated from the values read from
eeprom. Ideally the MAC addresses are updated sequencially. So if any
MAC address is invalid, it means there are no further valid values.
So optimise this logic by replacing continue with break.

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/efef0d07add5d5777396ea111ad75411dc402db3.1645624855.git.michal.simek@xilinx.com