wil6210: remove support for old hardware

Hardware older than Sparrow B0 obsolete.
There is no WiFi product that uses this hardware.
Recent firmware does not support it either.

Remove driver support.

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>