ARM: S3C24XX: Use module_platform_driver macro in mach-osiris-dvs.c

module_platform_driver simplifies the code by eliminating
module_init and module_exit calls.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>