video: Drop DEV_FLAGS_SYSTEM flag

DEV_FLAGS_SYSTEM does not have any actual meaning, hence drop it.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/video/cfb_console.c b/drivers/video/cfb_console.c
index aa7ca86..51cdd4d 100644
--- a/drivers/video/cfb_console.c
+++ b/drivers/video/cfb_console.c
@@ -2281,7 +2281,7 @@
 	memset(&console_dev, 0, sizeof(console_dev));
 	strcpy(console_dev.name, "vga");
 	console_dev.ext = DEV_EXT_VIDEO;	/* Video extensions */
-	console_dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_SYSTEM;
+	console_dev.flags = DEV_FLAGS_OUTPUT;
 	console_dev.putc = video_putc;	/* 'putc' function */
 	console_dev.puts = video_puts;	/* 'puts' function */