media: stm32-dcmi: add support of 1X16 serial pixel formats variant

Add support of 1X16 serial pixel formats in order to support
CSI-2 camera sensor exposing 1x16 pixel formats only.

Signed-off-by: Hugues Fruchet <hugues.fruchet@st.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>