sh: Update gpio_set_value() pin value handling

This patch updates the pinmux code to use the boolean value for
the function gpio_set_value(). Without this patch values other
than 0 and 1 will result in incorrect GPIO settings.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>