x86/acpi: Update MADT table version

Update the MADT table version to sync with the FADT table version.
All current coreboot FADT tables are set to ACPI_FADT_REV_ACPI_3_0
and the MADT should be set to match.

This error was found by running FWTS:
FAILED [MEDIUM] SPECMADTFADTRevisions: Test 2, MADT revision is not in sync with
the FADT revision; MADT 1 expects FADT 3.0 but found 4.0 instead.

BUG=b:112476331
TEST-Run FWTS

Change-Id: If5ef53794ff80dd21f13c247d17c2a0e9f9068f2
Signed-off-by: Marc Jones <marcj303@gmail.com>
Reviewed-on: https://review.coreboot.org/28256
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/arch/x86/acpi.c b/src/arch/x86/acpi.c
index e6d8ee0..012fe18 100644
--- a/src/arch/x86/acpi.c
+++ b/src/arch/x86/acpi.c
@@ -1263,7 +1263,7 @@
 	case FADT:
 		return ACPI_FADT_REV_ACPI_3_0;
 	case MADT: /* ACPI 1.0/2.0: 1, ACPI 3.0: 2, ACPI 4.0: 3 */
-		return 1;
+		return 2;
 	case MCFG:
 		return 1;
 	case TCPA: