USB: gadget: __init and __exit tags removed

__init, __initdata and __exit tags have have been removed from
various files to make it possible for gadgets that do not use
the __init/__exit tags to use those.

Files in question are related to:
* the core composite framework,
* the mass storage function (fixing a section mismatch) and
* ethernet driver (ACM, ECM, RNDIS).

Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>