arch/x86/smbios.c: Use macro for 'type_detail'

Change-Id: I95c40acb2fb390c50c8d1af9dd44999f9d57c2d5
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43589
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/arch/x86/smbios.c

@@ -360,7 +360,7 @@ static int create_smbios_type17_for_dimm(struct dimm_info *dimm,
 	t->maximum_voltage = dimm->vdd_voltage;
 
 	/* Synchronous = 1 */
-	t->type_detail = 0x0080;
+	t->type_detail = MEMORY_TYPE_DETAIL_SYNCHRONOUS;
 	/* no handle for error information */
 	t->memory_error_information_handle = 0xFFFE;
 	t->attributes = dimm->rank_per_dimm;