pinctrl: imx6q: make it explicitly non-modular

The Kconfig currently controlling compilation of this code is:

drivers/pinctrl/freescale/Kconfig:config PINCTRL_IMX6Q
drivers/pinctrl/freescale/Kconfig:	bool "IMX6Q/DL pinctrl driver"

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

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.

We don't replace module.h with init.h since the file already has that.
But we do add export.h since this file uses the global THIS_MODULE.

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: Dong Aisheng <dong.aisheng@linaro.org>
Cc: linux-gpio@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>