Revert "ath: add support for special 0x0 regulatory domain"

stable inclusion
from stable-v5.10.109
commit 87f7ed7c36596f76fc8e9d07c7efc800e76d4e33
bugzilla: https://gitee.com/openeuler/kernel/issues/I574AE

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=87f7ed7c36596f76fc8e9d07c7efc800e76d4e33

--------------------------------

commit 1ec7ed51 upstream.

This reverts commit 2dc01659.

Users are reporting regressions in regulatory domain detection and
channel availability.

The problem this was trying to resolve was fixed in firmware anyway:

    QCA6174 hw3.0: sdio-4.4.1: add firmware.bin_WLAN.RMH.4.4.1-00042
    https://github.com/kvalo/ath10k-firmware/commit/4d382787f0efa77dba40394e0bc604f8eff82552

Link: https://bbs.archlinux.org/viewtopic.php?id=254535
Link: http://lists.infradead.org/pipermail/ath10k/2020-April/014871.html
Link: http://lists.infradead.org/pipermail/ath10k/2020-May/015152.html
Link: https://lore.kernel.org/all/1c160dfb-6ccc-b4d6-76f6-4364e0adb6dd@reox.at/
Fixes: 2dc01659 ("ath: add support for special 0x0 regulatory domain")
Cc: <stable@vger.kernel.org>
Cc: Wen Gong <wgong@codeaurora.org>
Signed-off-by: NBrian Norris <briannorris@chromium.org>
Signed-off-by: NKalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20200527165718.129307-1-briannorris@chromium.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/net/wireless/ath/regd.c

@@ -666,14 +666,14 @@ ath_regd_init_wiphy(struct ath_regulatory *reg,
 
 /*
  * Some users have reported their EEPROM programmed with
- * 0x8000 or 0x0 set, this is not a supported regulatory
- * domain but since we have more than one user with it we
- * need a solution for them. We default to 0x64, which is
- * the default Atheros world regulatory domain.
+ * 0x8000 set, this is not a supported regulatory domain
+ * but since we have more than one user with it we need
+ * a solution for them. We default to 0x64, which is the
+ * default Atheros world regulatory domain.
  */
 static void ath_regd_sanitize(struct ath_regulatory *reg)
 {
-	if (reg->current_rd != COUNTRY_ERD_FLAG && reg->current_rd != 0)
+	if (reg->current_rd != COUNTRY_ERD_FLAG)
 		return;
 	printk(KERN_DEBUG "ath: EEPROM regdomain sanitized\n");
 	reg->current_rd = 0x64;