Adding different macro mtk_v4l2_vdec_dbg and mtk_v4l2_venc_dbg for
encoder and decoder. Then calling the common macro mtk_v4l2_debug to
print debug message.

Replace pr_err with dev_err for 'mtk_v4l2_err' debug message.
Replace pr_debug with dev_dbg for 'mtk_v4l2_debug' debug message.
Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>