video: Convert CONFIG_VIDEO_LOGO to Kconfig

This converts the following to Kconfig:
   CONFIG_VIDEO_LOGO

Note that this option depends on CONFIG_DM_VIDEO now, since cfb_console is
deprecated. The only relevant code is now in splash.c

Drop the check for DM_VIDEO in that file.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/splash.c b/common/splash.c
index de720df..98f0089 100644
--- a/common/splash.c
+++ b/common/splash.c
@@ -52,7 +52,7 @@
 	},
 };
 
-#if defined(CONFIG_DM_VIDEO) && defined(CONFIG_VIDEO_LOGO)
+#ifdef CONFIG_VIDEO_LOGO
 
 #include <bmp_logo_data.h>