drm/exynos: Add plane support with fimd

The exynos fimd supports 5 window overlays. Only one window overlay of
fimd is used by the crtc, so we need plane feature to use the rest
window overlays.

This creates one ioctl exynos specific - DRM_EXYNOS_PLANE_SET_ZPOS, it
is the ioctl to decide for user to assign which window overlay.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drivers/gpu/drm/exynos/Makefile

@@ -5,7 +5,8 @@
 ccflags-y := -Iinclude/drm -Idrivers/gpu/drm/exynos
 exynosdrm-y := exynos_drm_drv.o exynos_drm_encoder.o exynos_drm_connector.o \
 		exynos_drm_crtc.o exynos_drm_fbdev.o exynos_drm_fb.o \
-		exynos_drm_buf.o exynos_drm_gem.o exynos_drm_core.o
+		exynos_drm_buf.o exynos_drm_gem.o exynos_drm_core.o \
+		exynos_drm_plane.o
 
 obj-$(CONFIG_DRM_EXYNOS) += exynosdrm.o
 obj-$(CONFIG_DRM_EXYNOS_FIMD) += exynos_drm_fimd.o