arm64: zynqmp: Enable mac address randomization for zc1751 dc5

There is no memory which stores mac address that's why generate it.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

configs/xilinx_zynqmp_zc1751_xm019_dc5_defconfig

@@ -35,6 +35,7 @@ CONFIG_CMD_EXT4_WRITE=y
 CONFIG_SPL_OF_CONTROL=y
 CONFIG_OF_EMBED=y
 CONFIG_ENV_IS_IN_FAT=y
+CONFIG_NET_RANDOM_ETHADDR=y
 CONFIG_SPL_DM=y
 CONFIG_SPL_DM_SEQ_ALIAS=y
 CONFIG_CLK_ZYNQMP=y