pinctrl: mediatek: Fix some off by one bugs

These comparisons should be >= instead of > to prevent accessing one
element beyond the end of the hw->soc->pins[] array.

Fixes: 3de7deef ("pinctrl: mediatek: Check gpio pin number and use binary search in mtk_hw_pin_field_lookup()")
Fixes: 184d8e13

 ("pinctrl: mediatek: Add support for pin configuration dump via debugfs.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20200218055247.74s2xa7veqx2do34@kili.mountain
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>