pinctrl: mediatek: data struct optimize and remove unused member

struct mtk_desc_pin.chip, mtk_pinctrl_devdata.invser_offset
and mtk_pinctrl_devdata.chip_type are never used in code.
Remove them.

Some per-pin data are using int for pin number and offsets.
Change to short and rearrange to reduce const data size.

Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
Signed-off-by: Hongzhou Yang <hongzhou.yang@mediatek.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>