[ARM] Add memory.txt to 00-INDEX

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/Documentation/arm/00-INDEX b/Documentation/arm/00-INDEX
index d753fe5..2c6a3b3 100644
--- a/Documentation/arm/00-INDEX
+++ b/Documentation/arm/00-INDEX
@@ -16,5 +16,7 @@
 	- Empeg documentation
 mem_alignment
 	- alignment abort handler documentation
+memory.txt
+	- description of the virtual memory layout
 nwfpe
 	- NWFPE floating point emulator documentation