x86: add two missing unwind annotations

Impact: improve debuginfo
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/entry_64.S

@@ -255,6 +255,7 @@ ENTRY(ret_from_fork)
 	call schedule_tail
 	GET_THREAD_INFO(%rcx)
 	testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),TI_flags(%rcx)
+	CFI_REMEMBER_STATE
 	jnz rff_trace
 rff_action:	
 	RESTORE_REST
@@ -264,6 +265,7 @@ rff_action:
 	jnz  int_ret_from_sys_call
 	RESTORE_TOP_OF_STACK %rdi,ARGOFFSET
 	jmp ret_from_sys_call
+	CFI_RESTORE_STATE
 rff_trace:
 	movq %rsp,%rdi
 	call syscall_trace_leave