[media] exynos4-is: Add support for Exynos5250 MIPI-CSIS

Add compatible property for the Exynos5250 and enable the frame start
and frame end interrupts. These interrupts are needed for the Exynos5
FIMC-IS firmware. The driver enables those interrupt only where available,
depending on the 'compatible' property. This can be optimized further,
by exposing some API at the subdev driver, so the host driver can enable
extra interrupts only for the image processing chains involving FIMC-IS.

Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>