drm/exynos: control blending of mixer graphic layer 0
drm/exynos: control blending of mixer graphic layer 0

The mixer graphic layer 0 isn't blended as default by commit
0377f4ed9f1aed30292c4e3c87f24e028ae26f36(drm/exynos: Don't blend mixer
layer 0). But it needs to be blended with graphic layer 0 if video layer
is enabled by vp because video layer is bottom.

Signed-off-by: Joonyoung Shim <b2207686f8c5343cf0f505ae1d5720ecb0c3202a@samsung.com>
Signed-off-by: Inki Dae <bae4a7a27bbc965064e97edd6e179ac4979db440@samsung.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs