pinctrl: pinctrl-single: remove unused parameter

Remove unused parameter 'pin_pos' from pcs_add_pin().

Signed-off-by: Hanna Hawa <hhhawa@amazon.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Drew Fustini <drew@beagleboard.org>
Link: https://lore.kernel.org/r/20210319152133.28705-3-hhhawa@amazon.com


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