pinctrl: stm32: Add check for devm_kcalloc

Add check for the return value of devm_kcalloc() and return the error
if it fails in order to avoid NULL pointer dereference.

Fixes: 32c170ff ("pinctrl: stm32: set default gpio line names using pin names")
Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Acked-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20231031080807.3600656-1-nichen@iscas.ac.cn


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>