msm: documentation: add gpiomux documentation.

Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
diff --git a/Documentation/arm/00-INDEX b/Documentation/arm/00-INDEX
index 7f5fc3b..ecf7d04 100644
--- a/Documentation/arm/00-INDEX
+++ b/Documentation/arm/00-INDEX
@@ -6,6 +6,8 @@
 	- ARM Interrupt subsystem documentation
 IXP2000
 	- Release Notes for Linux on Intel's IXP2000 Network Processor
+msm
+	- MSM specific documentation
 Netwinder
 	- Netwinder specific documentation
 Porting