clk: sunxi: make clk-* explicitly non-modular

We have the following file --> Kconfig mapping:

sunxi/clk-factors.c              obj-y
sunxi/clk-sun6i-apb0-gates.c     CONFIG_MFD_SUN6I_PRCM (bool)
sunxi/clk-sun6i-apb0.c           CONFIG_MFD_SUN6I_PRCM
sunxi/clk-sun6i-ar100.c          CONFIG_MFD_SUN6I_PRCM
sunxi/clk-sun8i-apb0.c           CONFIG_MFD_SUN6I_PRCM
sunxi/clk-sun9i-mmc.c            obj-y

Hence none of these are being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the drivers there is no doubt they are builtin-only.  All
drivers get mostly the same changes, so they are handled in batch.

Changes are (1) convert to builtin_platform_register, (2) use the
init.h header, (3) delete the MODULE_LICENCE/MODULE_AUTHOR and
associated tags, and (4) delete any ".remove" functions.

There was a stray module.h in a file not using any init.h or
module.h stuff, so we simply removed that one.

In two cases, we explicitly disallow a driver unbind, since that
doesn't have a sensible use case anyway, and it allows us to drop
the ".remove" code for non-modular drivers.

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

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

Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: "Emilio López" <emilio@elopez.com.ar>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: linux-clk@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20160704211220.5685-9-paul.gortmaker@windriver.com