cfg80211: Add support to calculate and report 4096-QAM HE rates

Drivers supporting 4096-QAM rates as a vendor extension in HE mode need
to update the correct rate info to userspace while using 4096-QAM (MCS12
and MCS13) in HE mode. Add support to calculate bitrates of HE-MCS12 and
HE-MCS13 which represent the 4096-QAM modulation schemes. The MCS12 and
MCS13 bitrates are defined in IEEE P802.11be/D0.1.

In addition, scale up the bitrates by 3*2048 in order to accommodate
calculations for the new MCS12 and MCS13 rates without losing fraction
values.
Signed-off-by: Vamsi Krishna <vamsin@codeaurora.org>
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Link: https://lore.kernel.org/r/20201029183457.7005-1-jouni@codeaurora.orgSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/util.c

@@ -1276,20 +1276,22 @@ static u32 cfg80211_calculate_bitrate_vht(struct rate_info *rate)
 
 static u32 cfg80211_calculate_bitrate_he(struct rate_info *rate)
 {
-#define SCALE 2048
-	u16 mcs_divisors[12] = {
-		34133, /* 16.666666... */
-		17067, /*  8.333333... */
-		11378, /*  5.555555... */
-		 8533, /*  4.166666... */
-		 5689, /*  2.777777... */
-		 4267, /*  2.083333... */
-		 3923, /*  1.851851... */
-		 3413, /*  1.666666... */
-		 2844, /*  1.388888... */
-		 2560, /*  1.250000... */
-		 2276, /*  1.111111... */
-		 2048, /*  1.000000... */
+#define SCALE 6144
+	u32 mcs_divisors[14] = {
+		102399, /* 16.666666... */
+		 51201, /*  8.333333... */
+		 34134, /*  5.555555... */
+		 25599, /*  4.166666... */
+		 17067, /*  2.777777... */
+		 12801, /*  2.083333... */
+		 11769, /*  1.851851... */
+		 10239, /*  1.666666... */
+		  8532, /*  1.388888... */
+		  7680, /*  1.250000... */
+		  6828, /*  1.111111... */
+		  6144, /*  1.000000... */
+		  5690, /*  0.926106... */
+		  5120, /*  0.833333... */
 	};
 	u32 rates_160M[3] = { 960777777, 907400000, 816666666 };
 	u32 rates_969[3] =  { 480388888, 453700000, 408333333 };
@@ -1301,7 +1303,7 @@ static u32 cfg80211_calculate_bitrate_he(struct rate_info *rate)
 	u64 tmp;
 	u32 result;
 
-	if (WARN_ON_ONCE(rate->mcs > 11))
+	if (WARN_ON_ONCE(rate->mcs > 13))
 		return 0;
 
 	if (WARN_ON_ONCE(rate->he_gi > NL80211_RATE_INFO_HE_GI_3_2))