mcb: Replace ioremap and request_region with the devm version

Replaced ioremap with devm_ioremap and request_mem_region with
devm_request_mem_region. This makes the code much more cleaner.

Signed-off-by: Andreas Werner <andreas.werner@men.de>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>