pinctrl: rockchip: make it explicitly non-modular

The Kconfig currently controlling compilation of this code is:

drivers/pinctrl/Kconfig:config PINCTRL_ROCKCHIP
drivers/pinctrl/Kconfig:        bool

...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.

Note that MODULE_DEVICE_TABLE is a no-op for non-modular code.

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

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: linux-gpio@vger.kernel.org
Cc: linux-rockchip@lists.infradead.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>