iwlwifi: correct 6000 EEPROM regulatory address

For 6000 series, the 2.4G HT40 band regulatory settings address in EEPROM
was off by 2.

Before the fix, you'll see this in dmesg:
[79535.788877] ieee80211 phy8: U iwl_mod_ht40_chan_info HT40 Ch. 7 [2.4GHz]
WIDE (0x61 0dBm): Ad-Hoc not supported
[79535.788880] ieee80211 phy8: U iwl_mod_ht40_chan_info HT40 Ch. 11 [2.4GHz]
WIDE (0x61 0dBm): Ad-Hoc not supported

And after the fix:
[91132.688706] ieee80211 phy14: U iwl_mod_ht40_chan_info HT40 Ch. 7 [2.4GHz]
IBSS ACTIVE WIDE (0x6f 0dBm): Ad-Hoc supported
[91132.688709] ieee80211 phy14: U iwl_mod_ht40_chan_info HT40 Ch. 11 [2.4GHz]
IBSS ACTIVE WIDE (0x6f 0dBm): Ad-Hoc supported

Signed-off-by: Shanyu Zhao <shanyu.zhao@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>