pinctrl: stmfx: add irq_request/release_resources callbacks

pinctrl: stmfx: add irq_request/release_resources callbacks

When an STMFX IO is used as interrupt through the interrupt-controller
binding, the STMFX driver should configure this IO as input. Default
value of STMFX IO direction is input, but if the IO is used as output
before the interrupt use, it will not work without these callbacks.

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Link: https://lore.kernel.org/r/20191009091606.17283-1-amelie.delaunay@st.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>