i386: add TRACE_IRQS_OFF for exception 1 (debug)

At this point interrupts are off, so let's inform the tracing
code of that fact before calling into C.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/entry_32.S

@@ -804,6 +804,7 @@ debug_stack_correct:
 	pushl $-1			# mark this as an int
 	CFI_ADJUST_CFA_OFFSET 4
 	SAVE_ALL
+	TRACE_IRQS_OFF
 	xorl %edx,%edx			# error code 0
 	movl %esp,%eax			# pt_regs pointer
 	call do_debug