stm32mp1: Add GPIO support

The management of pinctrl nodes of device tree is also added.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Signed-off-by: Mathieu Belou <mathieu.belou@st.com>
Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@st.com>
diff --git a/plat/st/stm32mp1/platform.mk b/plat/st/stm32mp1/platform.mk
index e26504f..46b7fbd 100644
--- a/plat/st/stm32mp1/platform.mk
+++ b/plat/st/stm32mp1/platform.mk
@@ -41,6 +41,7 @@
 				drivers/delay_timer/generic_delay_timer.c		\
 				drivers/st/clk/stm32mp1_clk.c				\
 				drivers/st/clk/stm32mp1_clkfunc.c			\
+				drivers/st/gpio/stm32_gpio.c				\
 				drivers/st/reset/stm32mp1_reset.c			\
 				plat/st/stm32mp1/stm32mp1_dt.c				\
 				plat/st/stm32mp1/stm32mp1_helper.S