wifi: iwlwifi: mvm: fix warnings from dmi_get_system_info()

dmi_get_system_info() will statically return NULL when the
kernel is compiled without CONFIG_DMI, leading to compiler
warnings. Fix that by printing "<unknown>" in that case.

Fixes: c3f40c3e ("iwlwifi: mvm: add US/CA to TAS block list if OEM isn't allowed")
Fixes: 9457077d ("wifi: iwlwifi: mvm: Add debugfs to get TAS status")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

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

@@ -880,7 +880,7 @@ 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_is_tas_approved() ? "YES" : "NO");
 	pos += scnprintf(pos, endpos - pos,

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

@@ -1159,7 +1159,7 @@ static void iwl_mvm_tas_init(struct iwl_mvm *mvm)
 	if (!iwl_is_tas_approved()) {
 		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(data.block_list_array,
 						    &data.block_list_size,
 						    IWL_MCC_US)) ||
@@ -1173,7 +1173,7 @@ 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>");
 	}
 
 	fw_ver = iwl_fw_lookup_cmd_ver(mvm->fw, cmd_id,