media: platform: mtk-mdp3: dynamically allocate component clocks

For extensibility of adding more MDP3 components in the further, the
magic number is removed by dynamically allocating component clocks.

Signed-off-by: Moudy Ho <moudy.ho@mediatek.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>