hw/arm/virt: Wire up secure timer interrupt

Wire up the secure timer interrupt. Since we've defined
that the plain old physical timer is the NS timer, we can
drop the now-out-of-date comment about QEMU not having TZ.

Use a data-driven loop to wire up the timer interrupts, since
we now have four of them and the code is the same for each.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1437047249-2357-4-git-send-email-peter.maydell@linaro.org
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
