[media] s5p-jpeg: Fix output YUV 4:2:0 fourcc for decoder

Output samples during decoding phase for the YUV 4:2:0 format
are arranged in the manner compatible with 2-planar NV12,
not 3-planar YUV420 fourcc.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>