In the mass-conversion to the new irqchip callbacks, this
in-transit IRQ support was missed. Fix it.

Cc: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Cc: Maxime COQUELIN <maxime.coquelin@st.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>