sh: Add document for SuperH.

This document is a summary of information concerning SuperH of U-Boot.

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

doc/README.sh

+
+U-Boot for Renesas SuperH 
+	Last update 08/10/2007 by Nobuhiro Iwamatsu
+
+================================================================================
+0. What's this?
+	This file contains status information for the port of U-Boot to the
+	Renesas SuperH series of CPUs.
+
+================================================================================
+1. Overview
+	SuperH has an original boot loader. However, source code is dirty, and 
+	maintenance is not done.
+	To improve sharing and the maintenance of the code, Nobuhiro Iwamatsu 
+	started the porting to u-boot in 2007. 
+
+================================================================================
+2. Supported CPUs
+
+	2.1. Renesas SH7750/SH7750R
+	2.2. Renesas SH7722
+
+================================================================================
+3. Supported Boards
+
+	3.1. Hitachi UL MS7750SE01/MS7750RSE01
+		Board specific code is in board/ms7750se
+		To use this board, type "make ms7750se_config".
+
+	3.2. Hitachi UL MS7722SE01
+		Board specific code is in board/ms7722se
+		To use this board, type "make ms7722se_config".
+
+	** README **
+		In SuperH, S-record and binary of made u-boot work on the memory.
+		When u-boot is written in the flash, it is necessary to change the 
+		address by using 'objcopy'.  
+		ex) shX-linux-objcopy -Ibinary -Osrec u-boot.bin u-boot.flash.srec
+	
+================================================================================
+4. Compiler
+	You can use the following of u-boot to compile. 
+		- SuperH Linux Open site
+			http://www.superh-linux.org/
+		- KPIT GNU tools
+			http://www.kpitgnutools.com/
+
+================================================================================
+5. Future
+	I plan to support the following CPUs and boards.
+		5.1. CPUs
+			- SH7710/SH7712 (SH3)
+			- SH7780(SH4)
+			- SH7785(SH4)
+		
+		5.2. Boards
+			- Many boards ;-)
+
+================================================================================
+Copyright (c) 2007
+    Nobuhiro Iwamatsu <iwamatsu@nigaur.org>
+