wlcore: Prepare family to fix nvs file handling

Move struct wilink_family_data to be available for all TI WLAN
variants. And fix familiy typo, it should be just family.

Looks like wl12xx use two different nvs.bin files and wl18xx
uses a different conf.bin file.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>