intel-iommu: Set a more specific taint flag for invalid BIOS DMAR tables

We now know how to deal with these tables so that they are harmless.
Set TAINT_FIRMWARE_WORKAROUND instead of the default TAINT_WARN.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/pci/dmar.c

@@ -360,7 +360,9 @@ dmar_parse_one_rhsa(struct acpi_dmar_header *header)
 			return 0;
 		}
 	}
-	WARN(1, "Your BIOS is broken; RHSA refers to non-existent DMAR unit at %llx\n"
+	WARN_TAINT(
+		1, TAINT_FIRMWARE_WORKAROUND,
+		"Your BIOS is broken; RHSA refers to non-existent DMAR unit at %llx\n"
 		"BIOS vendor: %s; Ver: %s; Product Version: %s\n",
 		drhd->reg_base_addr,
 		dmi_get_system_info(DMI_BIOS_VENDOR),
@@ -620,7 +622,9 @@ int __init dmar_table_init(void)
 
 static void warn_invalid_dmar(u64 addr, const char *message)
 {
-	WARN_ONCE(1, "Your BIOS is broken; DMAR reported at address %llx%s!\n"
+	WARN_TAINT_ONCE(
+		1, TAINT_FIRMWARE_WORKAROUND,
+		"Your BIOS is broken; DMAR reported at address %llx%s!\n"
 		"BIOS vendor: %s; Ver: %s; Product Version: %s\n",
 		addr, message,
 		dmi_get_system_info(DMI_BIOS_VENDOR),