pinctrl: Relax user input size in pinmux_select()

This is debugfs and there is no much sense to strict the user from
sending as much data as they can. The memdup_user_nul() will anyway
fail if there is not enough memory.

Relax the user input size by removing an artificial limitaion.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230604131215.78847-2-andriy.shevchenko@linux.intel.com


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