The Kconfig currently controlling compilation of this code is:

drivers/mfd/Kconfig:config MFD_MAX77843
drivers/mfd/Kconfig:    bool "Maxim Semiconductor MAX77843 PMIC Support"

...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.

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_i2c_driver() uses the same init level priority as
builtin_i2c_driver() the init ordering remains unchanged with
this commit.

Also note that MODULE_DEVICE_TABLE is a no-op for non-modular code.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>