[media] exynos4-is: Add missing MODULE_LICENSE for exynos-fimc-is.ko

This fixes compilation warning:
WARNING: modpost: missing MODULE_LICENSE() in
drivers/media/platform/exynos4-is/exynos-fimc-is.o

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>