wifi: iwlwifi: mvm: rs: print BAD_RATE for invalid HT/VHT index

If there's a rate->index that maps inside the range but
to an uninitialized value, then that's also a bad rate,
avoid printing "(nil)" in that case and rather print the
"BAD_RATE" string instead as in the else branch.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230314194113.06b38d160fc5.I45a9254d3658b1ce796aa4c427193d3cbf638d7e@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/rs.c

@@ -512,10 +512,10 @@ static char *rs_pretty_rate(const struct rs_rate *rate)
 		 (rate->index <= IWL_RATE_MCS_9_INDEX))
 		rate_str = ht_vht_rates[rate->index];
 	else
-		rate_str = "BAD_RATE";
+		rate_str = NULL;
 
 	sprintf(buf, "(%s|%s|%s)", rs_pretty_lq_type(rate->type),
-		iwl_rs_pretty_ant(rate->ant), rate_str);
+		iwl_rs_pretty_ant(rate->ant), rate_str ?: "BAD_RATE");
 	return buf;
 }