nxp: remove soc name from siul2 pin control driver

The SIUL2 pin control driver is already a native driver that can be used
with any NXP SoC featuring the SIUL2 hw IP. Hence, rename all sources to
drop the "S32" family name so that other family of devices can make use
of it cleanly.

Signed-off-by: Manuel Argüelles <[email protected]>

Author: manuargue