drivers: pinctrl: Remove duplicate include of io.h

linux/io.h has been included at line 6, so remove the
duplicate include at line 18.

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Link: https://lore.kernel.org/r/20210323013727.135571-1-wanjiabing@vivo.com


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