cfg80211: add VHT rate entries for MCS-10 and MCS-11

Observed the warning in cfg80211_calculate_bitrate_vht() using an
11ac chip reporting MCS-11. Since devices reporting non-standard
MCS-9 is already supported add similar entries for MCS-10 and MCS-11.
Actually, the value of MCS-9@20MHz is slightly off so corrected that.

Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Link: https://lore.kernel.org/r/20210105105839.3795-1-arend.vanspriel@broadcom.com
[fix array size]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>