drm/exynos: use define instead of default_win member in struct mixer_context

The default_win member in struct mixer_context isn't change its value
after initialized to 0, so it's better using to define.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c
index 9c99514..563092e 100644
--- a/drivers/gpu/drm/exynos/exynos_mixer.c
+++ b/drivers/gpu/drm/exynos/exynos_mixer.c
@@ -38,6 +38,7 @@
 #include "exynos_drm_hdmi.h"
 
 #define MIXER_WIN_NR		3
+#define MIXER_DEFAULT_WIN	0
 
 #define get_mixer_context(dev)	platform_get_drvdata(to_platform_device(dev))
 
@@ -75,7 +76,6 @@
 };
 
 struct mixer_context {
-	unsigned int		default_win;
 	unsigned int		irq;
 	int			pipe;
 	bool			interlace;
@@ -640,7 +640,7 @@
 
 	win = overlay->zpos;
 	if (win == DEFAULT_ZPOS)
-		win = mixer_ctx->default_win;
+		win = MIXER_DEFAULT_WIN;
 
 	if (win < 0 || win > MIXER_WIN_NR) {
 		DRM_ERROR("overlay plane[%d] is wrong\n", win);
@@ -680,7 +680,7 @@
 	DRM_DEBUG_KMS("[%d] %s, win: %d\n", __LINE__, __func__, win);
 
 	if (win == DEFAULT_ZPOS)
-		win = mixer_ctx->default_win;
+		win = MIXER_DEFAULT_WIN;
 
 	if (win < 0 || win > MIXER_WIN_NR) {
 		DRM_ERROR("overlay plane[%d] is wrong\n", win);
@@ -703,7 +703,7 @@
 	DRM_DEBUG_KMS("[%d] %s, win: %d\n", __LINE__, __func__, win);
 
 	if (win == DEFAULT_ZPOS)
-		win = mixer_ctx->default_win;
+		win = MIXER_DEFAULT_WIN;
 
 	if (win < 0 || win > MIXER_WIN_NR) {
 		DRM_ERROR("overlay plane[%d] is wrong\n", win);