x86: entry_64.S - add missing ENDPROC

native_usergs_sysret64 is described as

	extern void native_usergs_sysret64(void)

so lets add ENDPROC here

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: heukelum@fastmail.fm
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index fbcf96b..7cf8d79 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -188,6 +188,7 @@
 ENTRY(native_usergs_sysret64)
 	swapgs
 	sysretq
+ENDPROC(native_usergs_sysret64)
 #endif /* CONFIG_PARAVIRT */