ARM: at91: add NAND partition table and index

Add NAND partition table, EK board support boot up NAND flash using
the same NAND partition table

Add Index in this file

Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>

doc/README.at91

@@ -1,5 +1,10 @@
 Atmel AT91 Evaluation kits
 
+Index
+  - I. Board mapping & boot media
+  - II. NAND partition table
+  - III. watchdog support
+
 I. Board mapping & boot media
 ------------------------------------------------------------------------------
 AT91SAM9260EK, AT91SAM9G20EK & AT91SAM9XEEK
@@ -144,7 +149,21 @@ Environment variables
 		make sama5d3xek_serialflash_config	- use serial flash
 
 
-II. Watchdog support
+II. NAND partition table
+
+	All the board support boot from NAND flash will use the following NAND
+	partition table
+
+		0x00000000 - 0x0003FFFF	bootstrap	(256 KiB)
+		0x00040000 - 0x000BFFFF u-boot		(512 KiB)
+		0x000C0000 - 0x000FFFFF env		(256 KiB)
+		0x00100000 - 0x0013FFFF env_redundant	(256 KiB)
+		0x00140000 - 0x0017FFFF spare		(256 KiB)
+		0x00180000 - 0x001FFFFF dtb		(512 KiB)
+		0x00200000 - 0x007FFFFF kernel		(6 MiB)
+		0x00800000 - 0xxxxxxxxx rootfs		(All left)
+
+III. Watchdog support
 
 	For security reasons, the at91 watchdog is running at boot time and,
 	if deactivated, cannot be used anymore.