scripts: genpinctrl: handle unsupported pindata gracefully

The latest STM32 Open Pin Data revision contains SoC descriptors that
are not handled properly by genpinctrl yet. These files are parsed
properly but trigger an exception during the pinctrl template rendering.

Add exception logic around template rendering so that problematic SoC files
are skipped - with an error message - instead of crashing the script, which
would otherwise prevent regeneration of DTSI for *all* SoCs.

This allows us to keep updating the pinctrl DTSI for supported SoCs
even when new SoCs requiring genpinctrl updates are added to Pin Data.

Co-authored-by: Mathieu Choplain <mathieu.choplain@st.com>
Signed-off-by: Georgij Cernysiov <geo.cgv@gmail.com>