pinctrl: mediatek: make mtk-common explicitly non-modular

pinctrl: mediatek: make mtk-common explicitly non-modular

The Makefile currently controlling compilation of this code is:

  drivers/pinctrl/mediatek/pinctrl-mtk-common.o
    ---> drivers/pinctrl/mediatek/Makefile:obj-y += pinctrl-mtk-common.o

...meaning that it currently is not being built as a module by anyone.

Lets remove the couple traces of modular infrastructure use, so that
when reading the driver there is no doubt it is builtin-only.

We delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.

We don't replace module.h with init.h since the file doesn't need that.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Hongzhou Yang <hongzhou.yang@mediatek.com>
Cc: linux-gpio@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>