media: s5p-mfc: Add support for rate controls in MFCv12

In MFCv12, the rc configs are changed with support for CBR loose,
CBR tight and Variable Bitrate (VBR) added.

Cc: linux-fsd@tesla.com
Signed-off-by: Smitha T Murthy <smithatmurthy@gmail.com>
Signed-off-by: Aakarsh Jain <aakarsh.jain@samsung.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>