pinctrl: stm32: don't print an error on probe deferral during clock get

pinctrl: stm32: don't print an error on probe deferral during clock get

Change STM32 pinctrl driver to not print an error trace when probe is
deferred due to clock resource. Probe defer issue (for clocks) could
occur during bank registering when some banks have already been registered.
In this case banks already registered should be released. To not waste time
in this case, it is better to check first if all clocks are available
before registering banks.

Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>
Link: https://lore.kernel.org/r/20200615125407.27632-2-alexandre.torgue@st.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>