[media] exynos4-is: Allow colorspace conversion at FIMC-LITE

The FIMC-LITE output DMA allows to configure different YUV order
than the order at the camera input interface. Thus there is some
limited colorspace conversion possible. This patch makes the
color format variable be per FIMC-LITE input/output, rather than
a global per device. This also fixes incorrect behavior where
color format at the FIMC-LITE.N subdev's source pad is modified
by VIDIOC_S_FMT ioctl on the related video node.
YUV order definitions are corrected so that we use notation:
         | byte3 | byte2 | byte1 | byte0
  -------+-------+-------+-------+------
  YCBYCR | CR    | Y     | CB    | Y
  YCRYCB | CB    | Y     | CR    | Y
  CBYCRY | Y     | CR    | Y     | CB
  CRYCBY | Y     | CB    | Y     | CR

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>