video: exynos_dp: remove redundant parameters

This patch cleans up few redundant parameters keeping
the same functionality intact.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
Signed-off-by: Jingoo Han <jg1.han@samsung.com>