drm/exynos: Fix build breakage on !DRM_EXYNOS_FIMD

Disabling the CONFIG_DRM_EXYNOS_FIMD (e.g. by enabling of CONFIG_FB_S3C)
leads to build error:

drivers/built-in.o: In function `exynos_dp_dpms':
binder.c:(.text+0xd6a840): undefined reference to `fimd_dp_clock_enable'
binder.c:(.text+0xd6ab54): undefined reference to `fimd_dp_clock_enable'

Fix this by changing direct call to fimd_dp_clock_enable() into optional
call to exynos_drm_crtc_ops->clock_enable(). Only the DRM_EXYNOS_FIMD
implements this op.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
diff --git a/drivers/gpu/drm/exynos/exynos_dp_core.c b/drivers/gpu/drm/exynos/exynos_dp_core.c
index 1dbfba5..441ef06 100644
--- a/drivers/gpu/drm/exynos/exynos_dp_core.c
+++ b/drivers/gpu/drm/exynos/exynos_dp_core.c
@@ -32,7 +32,6 @@
 #include <drm/bridge/ptn3460.h>
 
 #include "exynos_dp_core.h"
-#include "exynos_drm_fimd.h"
 
 #define ctx_from_connector(c)	container_of(c, struct exynos_dp_device, \
 					connector)
@@ -1066,6 +1065,8 @@
 
 static void exynos_dp_poweron(struct exynos_dp_device *dp)
 {
+	struct exynos_drm_crtc *crtc = dp_to_crtc(dp);
+
 	if (dp->dpms_mode == DRM_MODE_DPMS_ON)
 		return;
 
@@ -1076,7 +1077,8 @@
 		}
 	}
 
-	fimd_dp_clock_enable(dp_to_crtc(dp), true);
+	if (crtc->ops->clock_enable)
+		crtc->ops->clock_enable(dp_to_crtc(dp), true);
 
 	clk_prepare_enable(dp->clock);
 	exynos_dp_phy_init(dp);
@@ -1087,6 +1089,8 @@
 
 static void exynos_dp_poweroff(struct exynos_dp_device *dp)
 {
+	struct exynos_drm_crtc *crtc = dp_to_crtc(dp);
+
 	if (dp->dpms_mode != DRM_MODE_DPMS_ON)
 		return;
 
@@ -1102,7 +1106,8 @@
 	exynos_dp_phy_exit(dp);
 	clk_disable_unprepare(dp->clock);
 
-	fimd_dp_clock_enable(dp_to_crtc(dp), false);
+	if (crtc->ops->clock_enable)
+		crtc->ops->clock_enable(dp_to_crtc(dp), false);
 
 	if (dp->panel) {
 		if (drm_panel_unprepare(dp->panel))