In the legacy platform data case each TMU platform device handles a
single channel with a single IRQ for the platform device. Retrieve the
IRQ using the logical channel number instead of the hardware channel
number.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>