pinctrl: stm32: add stm32h743-pinctrl compatible

STM32H7 SoCs uses the same pinctrl block as found into
STM32F7 SoCs

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Vikas Manocha <vikas.manocha@st.com>