ath11k: convert ath11k_hw_params to an array

Convert to ath11k_hw_params to an array to make it possible add new hardware in
the future, for example IPQ6018 or QCA6390.

No functional changes. Compile tested only.

Signed-off-by: Anilkumar Kolli <akolli@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1592316055-24958-3-git-send-email-kvalo@codeaurora.org