sunxi: configs: streamline include/configs/sun*.h wrappers

For mostly historic reasons we had configuration headers for each
Allwinner CPU "family". These days they are mostly just including one
common header, with the rest being somewhat empty.
There were attempts to remove them, and to just use the one common header
to begin with, but this has implications to the build system, which me
might not be ready for, yet.

To document this behaviour, and to avoid something sneaking in over
time, make those files all the same (minus the CPU family name and
the copyrights), and add a comment explaining that.
This makes it easier to just remove those files later on, when needed
and possible.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/include/configs/sun8i.h b/include/configs/sun8i.h
index 106139d..b6cd8d3 100644
--- a/include/configs/sun8i.h
+++ b/include/configs/sun8i.h
@@ -2,21 +2,12 @@
 /*
  * (C) Copyright 2014 Chen-Yu Tsai <wens@csie.org>
  *
- * Configuration settings for the Allwinner A23 (sun8i) CPU
+ * Placeholder wrapper to allow addressing Allwinner A23 (and later) sun8i
+ * CPU based devices separately. Please do not add anything in here.
  */
-
 #ifndef __CONFIG_H
 #define __CONFIG_H
 
-/*
- * A23 specific configuration
- */
-
-#include <asm/arch/cpu.h>
-
-/*
- * Include common sunxi configuration where most the settings are
- */
 #include <configs/sunxi-common.h>
 
 #endif /* __CONFIG_H */