SDIO/SPI probes functions automatically add a default wlan interface on top
of registered wiphy, through wilc_cfg80211_init which in turn calls
wilc_netdev_ifc_init. However, bus is still not fully initialized when we
register corresponding net device (for example we still miss some private
driver data pointers), which for example makes it impossible to
retrieve MAC address from chip (which is supposed to be set on net device
before its registration) before registering net device. More generally, net
device registration should not be done until driver has fully initialized
everything and is ready to handle any operation  on the net device.

Prevent net device from being registered so early by doing it at the end of
probe functions. Apply this logic to both sdio and spi buses.
Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240514-mac_addr_at_probe-v2-2-afef09f1cd10@bootlin.com