wcn36xx: Define wcn3680 specific firmware parameters

This commit defines a firmware configuration for the wcn3680 which
represents a working downstream configuration. This configuration has been
successfully applied to the upstream driver with antecedent patches
resulting in the same or better through-put in comparison to the
downstream driver on the test hardware.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200910150747.2179122-3-bryan.odonoghue@linaro.org