drm/exynos/fimc: remove unused camera interface polarization code

Polarization was never configured for DRM-FIMC device, so fimc_set_polarity
function did nothing. In fact DRM does not use camera interface so there
is no point in configuring it.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>