wifi: ath12k: fix handling of 6 GHz rules

In the US country code, to avoid including 6 GHz rules in the 5 GHz rules
list, the number of 5 GHz rules is set to a default constant value of 4
(REG_US_5G_NUM_REG_RULES). However, if there are more than 4 valid 5 GHz
rules, the current logic will bypass the legitimate 6 GHz rules.

For example, if there are 5 valid 5 GHz rules and 1 valid 6 GHz rule, the
current logic will only consider 4 of the 5 GHz rules, treating the last
valid rule as a 6 GHz rule. Consequently, the actual 6 GHz rule is never
processed, leading to the eventual disabling of 6 GHz channels.

To fix this issue, instead of hardcoding the value to 4, use a helper
function to determine the number of 6 GHz rules present in the 5 GHz rules
list and ignore only those rules.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.3.1-00173-QCAHKSWPL_SILICONZ-1

Cc: stable@vger.kernel.org
Fixes: d8899132 ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Signed-off-by: Aditya Kumar Singh <aditya.kumar.singh@oss.qualcomm.com>
Link: https://patch.msgid.link/20250123-fix_6ghz_rules_handling-v1-1-d734bfa58ff4@oss.qualcomm.com


Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>