drm/exynos: fix tests for valid FIMD window number

Valid values for FIMD windows are from 0 to WINDOWS_NR-1
inclusive (5 windows in total). The WINDOWS_NR is also
a size of fimd_context.win_data array.
However, early-return tests for wrong values of windows
accepted a value of WINDOWS_NR which is out of bound
for fimd_context.win_data.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_fimd.c

@@ -381,7 +381,7 @@ static void fimd_win_mode_set(struct device *dev,
 	if (win == DEFAULT_ZPOS)
 		win = ctx->default_win;
 
-	if (win < 0 || win > WINDOWS_NR)
+	if (win < 0 || win >= WINDOWS_NR)
 		return;
 
 	offset = overlay->fb_x * (overlay->bpp >> 3);
@@ -506,7 +506,7 @@ static void fimd_win_commit(struct device *dev, int zpos)
 	if (win == DEFAULT_ZPOS)
 		win = ctx->default_win;
 
-	if (win < 0 || win > WINDOWS_NR)
+	if (win < 0 || win >= WINDOWS_NR)
 		return;
 
 	win_data = &ctx->win_data[win];
@@ -622,7 +622,7 @@ static void fimd_win_disable(struct device *dev, int zpos)
 	if (win == DEFAULT_ZPOS)
 		win = ctx->default_win;
 
-	if (win < 0 || win > WINDOWS_NR)
+	if (win < 0 || win >= WINDOWS_NR)
 		return;
 
 	win_data = &ctx->win_data[win];