pinctrl: zynq: make it explicitly non-modular

The Kconfig currently controlling compilation of this code is:

config PINCTRL_ZYNQ
        bool "Pinctrl driver for Xilinx Zynq"

...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_platform_driver() uses the same init level priority as
builtin_platform_driver() the init ordering remains unchanged with
this commit.

Also 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: Michal Simek <michal.simek@xilinx.com>
Cc: Sören Brinkmann" <soren.brinkmann@xilinx.com>
Cc: linux-gpio@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>