media: stm32: dcmipp: rename dcmipp_parallel into dcmipp_input

media: stm32: dcmipp: rename dcmipp_parallel into dcmipp_input

In preparation of the introduction of dcmipp csi input support, rename
the dcmipp_parallel subdev into a generic dcmipp_input which will be in
charge of handling both parallel input & csi input.
Only structures / variables / functions and file naming are changed without
any functional modifications.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>