rtw88: no need to send additional information to legacy firmware

The firmware of 11AC devices need more information to support more offload
functions, such as IQK. And 11N devices such as 8723D does not support
offload these function in firmware, there is no need to send these additional
information to firmware when it comes to 11N devices.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200422034607.28747-3-yhchuang@realtek.com