[media] exynos4-is: Initialize the ISP subdev sd->owner field

Set the subdevs owner module so the exynos4_fimc_is module cannot
be unloaded when the FIMC-IS driver is in use.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>