UPSTREAM: ARC: entry: fix syscall_trace_exit argument

commit b1c6ecfd upstream.

Function syscall_trace_exit expects pointer to pt_regs. However
r0 is also used to keep syscall return value. Restore pointer
to pt_regs before calling syscall_trace_exit.

Cc: <stable@vger.kernel.org>
Signed-off-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 852b02d1)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I054099e383f16bb22017dd088934ad856e7b6e0a