arch_debug_get_caller() was returning the return address of the wrong

stack frame (i.e. its own). Not sure what the comment is supposed to
mean. Tested with gcc 2 and 4.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22121 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/arch/x86/arch_debug.c

@@ -301,7 +301,7 @@ arch_debug_get_caller(void)
 	// be smart enough to save its original value.
 	struct stack_frame *frame = (struct stack_frame *)x86_read_ebp();
 
-	return (void *)frame->return_address;
+	return (void *)frame->previous->return_address;
 }