pinctrl: pinctrl-single: remove unused variable

Remove unused parameter 'num_pins_in_register' from
pcs_allocate_pin_table().

Reported-by: kernel test robot <lkp@intel.com>
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/20210319152133.28705-2-hhhawa@amazon.com


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