Export board-status info.

Rather than hunting version across compile tree in board_status,
export it by coreboot itself.

Change-Id: I7f055e6fc077134001ebdb11df7381bbdc71a1fc
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/6747
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/include/version.h

@@ -9,6 +9,7 @@ extern const char mainboard_part_number[];
 extern const char coreboot_version[];
 extern const char coreboot_extra_version[];
 extern const char coreboot_build[];
+extern const unsigned int coreboot_version_timestamp;
 
 /* When coreboot was compiled */
 extern const char coreboot_compile_time[];