video: exynos_mipi_dsi: Remove unused code

This code is never executed and hence removed.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>