gpio: mxc: drop unused MODULE_ tags from non-modular code

The Kconfig currently controlling compilation of this code is:

drivers/gpio/Kconfig:config GPIO_MXC
drivers/gpio/Kconfig:   def_bool y

...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
was (or is now) contained at the top of the file in the comments.
Note the original e-mail had a missing/typo'd @ symbol anyway.

We don't replace module.h with init.h since the file already has that.

Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Daniel Mack <daniel@caiaq.de>
Cc: Juergen Beisert <kernel@pengutronix.de>
Cc: linux-gpio@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>