dm: pinctrl: Avoid race condition on probe for UCLASS_PINCTRL

dm: pinctrl: Avoid race condition on probe for UCLASS_PINCTRL

In case of system with several pin-controller device, probe the first
UCLASS_PINCTRL by seq number (defined by alias) to avoid race condition
with I2C PINCONTROL driver for GPIO expander (GPIO expander need I2C bus,
I2C driver need PINCONFIG).

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