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.