exynos5420: fix compilation without parade video

Not all exynos 5420 based devices with an LCD also have a parade LVDS
bridge. So make sure compilation doesn't break if CONFIG_LCD is enabled
and CONFIG_VIDEO_PARADE is not.

As a side-effect move the parade functions from the exynos system header
file to its own file.
Signed-off-by: NSjoerd Simons <sjoerd.simons@collabora.co.uk>
Signed-off-by: NMinkyu Kang <mk7.kang@samsung.com>

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

@@ -41,7 +41,4 @@ void set_usbhost_mode(unsigned int mode);
 void set_system_display_ctrl(void);
 int exynos_lcd_early_init(const void *blob);
 
-/* Initialize the Parade dP<->LVDS bridge if present */
-int parade_init(const void *blob);
-
 #endif	/* _EXYNOS4_SYSTEM_H */

board/samsung/smdk5420/smdk5420.c

@@ -9,6 +9,7 @@
 #include <asm/io.h>
 #include <i2c.h>
 #include <lcd.h>
+#include <parade.h>
 #include <spi.h>
 #include <errno.h>
 #include <asm/gpio.h>

include/parade.h

+/*
+ * (C) Copyright 2012 Samsung Electronics
+ * Donghwa Lee <dh09.lee@samsung.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __PARADE_H__
+#define __PARADE_H__
+
+/* Initialize the Parade dP<->LVDS bridge if present */
+#ifdef CONFIG_VIDEO_PARADE
+int parade_init(const void *blob);
+#else
+static inline int parade_init(const void *blob) { return -1; }
+#endif
+
+#endif	/* __PARADE_H__ */