gpio: do not include <asm/arch/gpio.h> for ARCH_STI

As no gpio.h is defined in arch/arm/include/asm/arch-stih410,
to avoid compilation failure, do not include asm/arch/gpio.h.

This is needed for example when including sdhci.h, which include
asm/gpio.h>.

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