gpio: stm32f7: Add ops get_function

This patch adds gpio get_function ops support.
This function reports the state of a gpio.

Signed-off-by: Christophe Kerello <christophe.kerello@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
1 file changed