wcn36xx: Use V1 data structure to store supported rates

This patch converts the internal data structure used to store data-rates
from version 0 to version 1.

This allows us to extend out the internal storage to represent VHT
parameters.

Using the extended version 1 data-structure allows us to avoid a whole raft
of version 1 specific fixup functions.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200910150450.2178784-3-bryan.odonoghue@linaro.org