x86/dumpstack: Remove unneeded check in dump_trace()

Smatch complains that we have some inconsistent NULL checking.

If "task" were NULL then it would lead to a NULL dereference
later. We can remove this test because earlier on in the
function we have:

 if (!task)
	task = current;
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Clemens Ladisch <clemens@ladisch.de>
Link: http://lkml.kernel.org/r/20120128105246.GA25092@elgon.mountainSigned-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/dumpstack_64.c

@@ -129,7 +129,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 	if (!stack) {
 		if (regs)
 			stack = (unsigned long *)regs->sp;
-		else if (task && task != current)
+		else if (task != current)
 			stack = (unsigned long *)task->thread.sp;
 		else
 			stack = &dummy;