wlcore: add missing nvs file name info for wilink8

The following commits:
commit c815fdeb ("wlcore: spi: Populate config firmware data")
commit d776fc86 ("wlcore: sdio: Populate config firmware data")

Populated the nvs entry for wilink6 and wilink7 only while it is
still needed for wilink8 as well.
This broke user space backward compatibility when upgrading from older
kernels, as the alternate mac address would not be read from the nvs that
is present in the file system (lib/firmware/ti-connectivity/wl1271-nvs.bin)
causing mac address change of the wlan interface.

This patch fix this and update the structure field with the same default
nvs file name that has been used before.

In addition, some distros hold a default wl1271-nvs.bin in the file
system with a bogus mac address (deadbeef...) that overrides the mac
address that is stored inside the device.
Warn users about this bogus mac address and use the internal mac address

Fixes: c815fdeb ("wlcore: spi: Populate config firmware data")
Fixes: d776fc86 ("wlcore: sdio: Populate config firmware data")
Signed-off-by: Eyal Reizer <eyalr@ti.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>