ACPI: Rename FADT model and set it to zero

INT_MODEL defined in ACPI 1.0 and renamed to reserved since V 2.0.
The value for this field is zero but 1 is allowed to maintain
compatibility with ACPI 1.0.

So set this value to zero as we are using greater version than ACPI 1.0.

Change-Id: I910ead4e5618c958a7989f4c309a3a4bb938e31a
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/29986
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: David Guckian
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/southbridge/intel/ibexpeak/lpc.c

@@ -655,7 +655,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	u16 pmbase = pci_read_config16(dev, 0x40) & 0xfffe;
 	int c2_latency;
 
-	fadt->model = 1;
+	fadt->reserved = 0;
 
 	fadt->sci_int = 0x9;
 	fadt->smi_cmd = APM_CNT;