s390: Add build salt to the vDSO

The vDSO needs to have a unique build id in a similar manner
to the kernel and modules. Use the build salt macro.

Signed-off-by: Bastian Blank <waldi@debian.org>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Author: Bastian Blank

arch/s390/kernel/vdso/note.S

@@ -4,10 +4,13 @@
  * Here we can supply some information useful to userland.
  */
 
+#include <linux/build-salt.h>
 #include <linux/uts.h>
 #include <linux/version.h>
 #include <linux/elfnote.h>
 
 ELFNOTE_START(Linux, 0, "a")
 	.long LINUX_VERSION_CODE
 ELFNOTE_END
+
+BUILD_SALT