[media] media: v4l: remove single to multiplane conversion

This patch removes an implicit conversion between multi and single plane
formats from V4L2 framework. The conversion is to be performed by libv4l2.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>