pinctrl: stm32: add set_state ops

set_state_ops is kept under PINCTRL_FULL flag in order
to decrease memory footprint in some configuration.
PINCTRL_FULL can be enabled for debug purpose.

Signed-off-by: Christophe Kerello <christophe.kerello@st.com>
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>