EXYNOS: Add dummy definition to fix compilation dependency on CONFIG_EXYNOS_MIPI_DSIM

When only DP is used, we need not enable CONFIG_EXYNOS_MIPI_DSIM.
But if we do not select CONFIG_EXYNOS_MIPI_DSIM, exynos_fb.c throws
error saying exynos_mipi_dsi_init() not defined. So, we add
dummy definition for exynos_mipi_dsi_init when CONFIG_EXYNOS_MIPI_DSIM
is not defined.
Signed-off-by: NAjay Kumar <ajaykumar.rs@samsung.com>
Acked-by: NSimon Glass <sjg@chromium.org>
Acked-by: NDonghwa Lee <dh09.lee@samsung.com>
Signed-off-by: NMinkyu Kang <mk7.kang@samsung.com>

arch/arm/include/asm/arch-exynos/mipi_dsim.h

@@ -358,7 +358,14 @@ struct mipi_dsim_lcd_driver {
 	void	(*mipi_display_on)(struct mipi_dsim_device *dsim_dev);
 };
 
+#ifdef CONFIG_EXYNOS_MIPI_DSIM
 int exynos_mipi_dsi_init(void);
+#else
+static inline int exynos_mipi_dsi_init(void)
+{
+	return 0;
+}
+#endif
 
 /*
  * register mipi_dsim_lcd_driver object defined by lcd panel driver