mpc5200: Misc updates to a3m071 config header

This patch changes some features of the a3m071/a4m2k board support:

- Add bootcounter support
- Update MTD env default to correct values
- Add mtdparts to bootargs for mtd partitioning via kernel cmdline
- Added some default env variables for easy updating (kernel, dtb)
- Change README to the updated flash locations

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/board/a3m071/README b/board/a3m071/README
index a0fe832..112c47b 100644
--- a/board/a3m071/README
+++ b/board/a3m071/README
@@ -57,13 +57,13 @@
 => fdt print
 
 5. Save fdt to NOR flash:
-=> erase fc060000 fc07ffff
-=> cp.b 1800000 fc060000 10000
+=> erase fc180000 fc07ffff
+=> cp.b 1800000 fc180000 10000
 
 All this can be integrated into an environment command:
-=> setenv upd_fdt 'tftp 1800000 a3m071/a3m071.dtb;run mtdargs addip2 addtty; \
-	fdt addr 1800000;fdt boardsetup;fdt chosen;erase fc060000 fc07ffff; \
-	cp.b 1800000 fc060000 10000'
+=> setenv upd_fdt 'tftp 1800000 a3m071/a3m071.dtb;run mtdargs addip addtty; \
+	fdt addr 1800000;fdt boardsetup;fdt chosen;erase fc180000 fc07ffff; \
+	cp.b 1800000 fc180000 10000'
 => saveenv
 
 After this, only "run upd_fdt" needs to get called to load, patch