include: Add 'IWYU pragma: export' comment

This pragma says to IWYU (Include What You Use) that the current file
is supposed to provide commented header.

Change-Id: I3acb5e6b18443e454d8174b0b1f9d207c0fb78b5
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81824
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <ericllai@google.com>

src/include/device/device.h

@@ -5,9 +5,9 @@
 #define DEVICE_H
 
 #include <console/console.h>
-#include <device/path.h>
+#include <device/path.h> /* IWYU pragma: export */
 #include <device/pci_type.h>
-#include <device/resource.h>
+#include <device/resource.h> /* IWYU pragma: export */
 #include <smbios.h>
 #include <static.h>
 #include <stdlib.h>

src/include/timestamp.h

@@ -3,7 +3,7 @@
 #ifndef __TIMESTAMP_H__
 #define __TIMESTAMP_H__
 
-#include <commonlib/timestamp_serialized.h>
+#include <commonlib/timestamp_serialized.h> /* IWYU pragma: export */
 #include <stdint.h>
 
 #if CONFIG(COLLECT_TIMESTAMPS)