lib/version: Move board identification strings

These strings are now only expanded in lib/identity.c.

This improves ccache hit rates slightly, as one built object file
lib/version.o is used for all variants of a board. Also one built
object file lib/identity.o can become a ccache hit for successive
builds of a variant, while the commit hash changes.

Change-Id: Ia7d5454d95c8698ab1c1744e63ea4c04d615bb3b
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74449
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/include/device/device.h

@@ -174,8 +174,6 @@ extern DEVTREE_CONST struct device * DEVTREE_CONST all_devices;
 extern struct resource	*free_resources;
 extern struct bus	*free_links;
 
-extern const char mainboard_name[];
-
 /* Generic device interface functions */
 struct device *alloc_dev(struct bus *parent, struct device_path *path);
 void dev_initialize_chips(void);

src/include/identity.h

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef IDENTITY_H
+#define IDENTITY_H
+
+/* Motherboard Information */
+extern const char mainboard_name[];
+extern const char mainboard_vendor[];
+extern const char mainboard_part_number[];
+
+#endif /* IDENTITY_H */

src/include/version.h

@@ -3,10 +3,6 @@
 #ifndef VERSION_H
 #define VERSION_H
 
-/* Motherboard Information */
-extern const char mainboard_vendor[];
-extern const char mainboard_part_number[];
-
 /* coreboot Version */
 extern const char coreboot_version[];
 extern const char coreboot_extra_version[];