drm/exynos: use helper to set possible crtcs

All encoders share the same code to set encoders possible_crtcs field.
The patch creates helper to abstract out this code.

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