ARM: i.MX video: declare displays and display_count publicly

Declare displays[] and display_count in imx-common/video.h to
prevent "Should it be static?" messages when compiling board
files with "make C=1".

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>

arch/arm/imx-common/video.c

@@ -6,9 +6,6 @@
 #include <asm/errno.h>
 #include <asm/imx-common/video.h>
 
-extern struct display_info_t const displays[];
-extern size_t display_count;
-
 int board_video_skip(void)
 {
 	int i;

arch/arm/include/asm/imx-common/video.h

@@ -21,4 +21,9 @@ struct display_info_t {
 extern int detect_hdmi(struct display_info_t const *dev);
 #endif
 
+#ifdef CONFIG_IMX_VIDEO_SKIP
+extern struct display_info_t const displays[];
+extern size_t display_count;
+#endif
+
 #endif