ipq40xx: ipqess: pass up ethdev_addr probe defer

ipq40xx: ipqess: pass up ethdev_addr probe defer

Notify via dev_info when a random MAC address is set.
of_get_ethdev_address can return -EPROBE_DEFER for NVMEM devices,
return this up, so that ipqess can defer as well.
Also move this MAC assignment from _init into _probe, so that this defer
can happen earlier.

Before change, with MAC address allocated from a built-in NVMEM layout
driver (mikrotik,routerboot-nvmem) with extra of_get_ethdev_address
result and random MAC printfs:
[    1.197571] ipqess-edma c080000.ethernet: ipqess_init of_get_ethdev_address ret:-517, of_node: /soc/ethernet@c080000
[    1.197690] ipqess-edma c080000.ethernet: generated random MAC address 22:e7:36:e0:e4:a3
[    1.614444] ipqess-edma c080000.ethernet eth0: entered promiscuous mode
[    5.055929] ipqess-edma c080000.ethernet eth0: configuring for fixed/internal link mode

after change:
[    1.173776] ipqess-edma c080000.ethernet: of_get_ethdev_address: -517
[    1.614607] ipqess-edma c080000.ethernet eth0: entered promiscuous mode
[    5.246105] ipqess-edma c080000.ethernet eth0: configuring for fixed/internal link mode
[    5.260754] ipqess-edma c080000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx

with extra __func__ printf to show _probe and _init:
[    1.173685] ipqess-edma c080000.ethernet: ipqess_axi_probe
[    1.173784] ipqess-edma c080000.ethernet: of_get_ethdev_address: -517
[    1.280347] ipqess-edma c080000.ethernet: ipqess_axi_probe
[    1.304844] ipqess-edma c080000.ethernet: ipqess_init
[    1.614664] ipqess-edma c080000.ethernet eth0: entered promiscuous mode

Signed-off-by: John Thomson <git@johnthomson.fastmail.com.au>
Link: https://github.com/openwrt/openwrt/pull/15831
Signed-off-by: Robert Marko <robimarko@gmail.com>