mfd: ab8500: make sysctrl explicitly non-modular

mfd: ab8500: make sysctrl explicitly non-modular

The Kconfig currently controlling compilation of this code is:

drivers/mfd/Kconfig:config AB8500_CORE
drivers/mfd/Kconfig:    bool "ST-Ericsson AB8500 Mixed Signal Power Management chip"

...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 also delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.

We replace module.h with init.h and export.h -- the latter since the file
does make use of EXPORT_SYMBOL.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>