sb/intel/i82371eb/fadt.c: Use macro for 'flags' instead of magic number

Change-Id: I793afe81fbb9abef0d4178af9dc2e91c612b1b43
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44521
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/southbridge/intel/i82371eb/fadt.c b/src/southbridge/intel/i82371eb/fadt.c
index 5add01c..5aeff4e 100644
--- a/src/southbridge/intel/i82371eb/fadt.c
+++ b/src/southbridge/intel/i82371eb/fadt.c
@@ -102,7 +102,8 @@
 	 * 18   FORCE_APIC_CLUSTER_MODEL
 	 * 19   FORCE_APIC_PHYSICAL_DESTINATION_MODE
 	 */
-	fadt->flags |= 0xa5;
+	fadt->flags |= ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED | ACPI_FADT_SLEEP_BUTTON |
+		       ACPI_FADT_S4_RTC_WAKE;
 
 	fadt->x_pm1a_evt_blk.space_id = ACPI_ADDRESS_SPACE_IO;
 	fadt->x_pm1a_evt_blk.bit_width = fadt->pm1_evt_len * 8;