pinctrl: stm32: use the hwspin_lock_timeout_in_atomic() API

pinctrl: stm32: use the hwspin_lock_timeout_in_atomic() API

Use the hwspin_lock_timeout_in_atomic() API which is the most appropriated
here. Indeed:
- hwspin_lock_() is called after spin_lock_irqsave()
- the hwspin_lock_timeout() API relies on jiffies count which won't work
  if IRQs are disabled which is the case here.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>
Link: https://lore.kernel.org/r/20200615124456.27328-1-alexandre.torgue@st.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>