pinctrl: stm32: prevent the use of the secure protected pins

The hardware denies any access from the Linux non-secure world to the
secure-protected pins. Hence, prevent any driver to request such a pin.

Mark the secure-protected GPIO lines as invalid (.init_valid_mask) and
prevent the pinmux request / pinconf setting operations.
Identify the secure pins with "NO ACCESS" in the pinconf sysfs.

Signed-off-by: Fabien Dessenne <fabien.dessenne@foss.st.com>
Link: https://lore.kernel.org/r/20220502153114.283618-1-fabien.dessenne@foss.st.com


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