[PATCH v2] wifi: iwlwifi: Fix build warning when DMI is not enabled

[Sunil V L]

This driver currently assumes CONFIG_DMI is enabled along with ACPI.
This may not be true. Due to this, the kernel test bot reports new
warning like below for RISC-V allyesconfig builds.

>> drivers/net/wireless/intel/iwlwifi/fw/acpi.c:1190:25:
warning: '%s' directive argument is null [-Wformat-overflow=]

1190 | "System vendor '%s' is not in the approved list, disabling PPAG.\n",

Fix the warnings by printing "<unknown>" when DMI interface returns
NULL.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202311040602.sCjU3UXr-lkp@xxxxxxxxx/
Signed-off-by: Sunil V L <sunilvl@xxxxxxxxxxxxxxxx>
---
Changes since v1:
	1) Modified the fix not to add dependency on DMI in Kconfig as
	   per feedback from Johannes.

 drivers/net/wireless/intel/iwlwifi/fw/acpi.c     | 2 +-
 drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c | 2 +-
 drivers/net/wireless/intel/iwlwifi/mvm/fw.c      | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/fw/acpi.c b/drivers/net/wireless/intel/iwlwifi/fw/acpi.c
index b96f30d11644..8cbb426f97e0 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/acpi.c
+++ b/drivers/net/wireless/intel/iwlwifi/fw/acpi.c
@@ -1273,7 +1273,7 @@ bool iwl_acpi_is_ppag_approved(struct iwl_fw_runtime *fwrt)
 	if (!dmi_check_system(dmi_ppag_approved_list)) {
 		IWL_DEBUG_RADIO(fwrt,
 			"System vendor '%s' is not in the approved list, disabling PPAG.\n",
-			dmi_get_system_info(DMI_SYS_VENDOR));
+			dmi_get_system_info(DMI_SYS_VENDOR) ?: "<unknown>");
 			fwrt->ppag_flags = 0;
 			return false;
 	}
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
index 329c545f65fd..e0c519daffe2 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
@@ -882,7 +882,7 @@ static ssize_t iwl_dbgfs_tas_get_status_read(struct file *file,
 				 le16_to_cpu(rsp->block_list[i]));
 
 	pos += scnprintf(pos, endpos - pos, "\nOEM name: %s\n",
-			 dmi_get_system_info(DMI_SYS_VENDOR));
+			 dmi_get_system_info(DMI_SYS_VENDOR) ?: "<unknown>");
 	pos += scnprintf(pos, endpos - pos, "\tVendor In Approved List: %s\n",
 			 iwl_mvm_is_vendor_in_approved_list() ? "YES" : "NO");
 	pos += scnprintf(pos, endpos - pos,
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
index 403bd17b8b7a..c11ecb372dbc 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
@@ -1231,7 +1231,7 @@ static void iwl_mvm_tas_init(struct iwl_mvm *mvm)
 	if (!iwl_mvm_is_vendor_in_approved_list()) {
 		IWL_DEBUG_RADIO(mvm,
 				"System vendor '%s' is not in the approved list, disabling TAS in US and Canada.\n",
-				dmi_get_system_info(DMI_SYS_VENDOR));
+				dmi_get_system_info(DMI_SYS_VENDOR) ?: "<unknown>");
 		if ((!iwl_mvm_add_to_tas_block_list(cmd.v4.block_list_array,
 						    &cmd.v4.block_list_size,
 							IWL_TAS_US_MCC)) ||
@@ -1245,7 +1245,7 @@ static void iwl_mvm_tas_init(struct iwl_mvm *mvm)
 	} else {
 		IWL_DEBUG_RADIO(mvm,
 				"System vendor '%s' is in the approved list.\n",
-				dmi_get_system_info(DMI_SYS_VENDOR));
+				dmi_get_system_info(DMI_SYS_VENDOR) ?: "<unknown>");
 	}
 
 	/* v4 is the same size as v3, so no need to differentiate here */
-- 
2.39.2