exynos4-is: Add the FIMC-IS ISP capture DMA driver

exynos4-is: Add the FIMC-IS ISP capture DMA driver

Add a video capture node for the FIMC-IS ISP IP block. The Exynos4x12
FIMC-IS ISP IP block has 2 DMA interfaces that allow to capture raw
Bayer and YUV data to memory.  Currently only the DMA2 output is and
raw Bayer data capture is supported.

exynos4-is: Fix ISP DMA capture start/stop sequence

Ensure we wait until FIMC-IS executes a command, otherwise a division by
zero exception is thrown in the interrupt handler due to buf_count being
set to 0.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com