acpi/acpi.c: Add a method to generate IOAPIC DMAR entries from hw

This reads back the ioapic id from hardware.

Change-Id: I214557bbe963d1086f35f96efb1cb47950099eb3
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70267
Reviewed-by: Jonathan Zhang <jonzhang@fb.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/include/acpi/acpi.h b/src/include/acpi/acpi.h
index 57dbc65..f66f054 100644
--- a/src/include/acpi/acpi.h
+++ b/src/include/acpi/acpi.h
@@ -1432,6 +1432,8 @@
 unsigned long acpi_create_dmar_ds_ioapic(unsigned long current,
 					      u8 enumeration_id,
 					      u8 bus, u8 dev, u8 fn);
+unsigned long acpi_create_dmar_ds_ioapic_from_hw(unsigned long current,
+						 u32 addr, u8 bus, u8 dev, u8 fn);
 unsigned long acpi_create_dmar_ds_msi_hpet(unsigned long current,
 						u8 enumeration_id,
 						u8 bus, u8 dev, u8 fn);