drm/exynos: fix exynos_drm_component_del

This patch resolves the issue that component object isn't removed
correctly.

A given component object couldn't be placed to head of drm_component_list
so all component objects added to the drm_component_list should be checked
to remove the given component object.

Signed-off-by: Inki Dae <inki.dae@samsung.com>