[ARM] S3C24XX: Documentation: update platform docs

Update documentation in arch/arm/plat-s3c24xx
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

Documentation/arm/Samsung-S3C24XX/Overview.txt

@@ -12,6 +12,7 @@ Introduction
 
   Support for the S3C2400 series is in progress.
 
+
 Configuration
 -------------
 
@@ -38,6 +39,22 @@ Layout
   Register, kernel and platform data definitions are held in the
   arch/arm/mach-s3c2410 directory./include/mach
 
+arch/arm/plat-s3c24xx:
+
+  Files in here are either common to all the s3c24xx family,
+  or are common to only some of them with names to indicate this
+  status. The files that are not common to all are generally named
+  with the initial cpu they support in the series to ensure a short
+  name without any possibility of confusion with newer devices.
+
+  As an example, initially s3c244x would cover s3c2440 and s3c2442, but
+  with the s3c2443 which does not share many of the same drivers in
+  this directory, the name becomes invalid. We stick to s3c2440-<x>
+  to indicate a driver that is s3c2440 and s3c2442 compatible.
+
+  This does mean that to find the status of any given SoC, a number
+  of directories may need to be searched.
+
 
 Machines
 --------