wil6210: set platform features based on FW capabilities

In some cases the platform should be aware of the FW capabilities
to decide which feature to enable.
For example, FW can control the external REF clock for power saving.
Driver should notify the platform about that, to allow platform
power management optimization.

Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>