Create/use more directory structure in the Documentation/ tree.

Create Documentation/blockdev/ sub-directory and populate it.
Populate the Documentation/serial/ sub-directory.
Move MSI-HOWTO.txt to Documentation/PCI/.
Move ioctl-number.txt to Documentation/ioctl/.
Update all relevant 00-INDEX files.
Update all relevant Kconfig files and source files.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
diff --git a/drivers/char/specialix.c b/drivers/char/specialix.c
index 242fd46..a16b94f 100644
--- a/drivers/char/specialix.c
+++ b/drivers/char/specialix.c
@@ -72,7 +72,7 @@
 /*
  * There is a bunch of documentation about the card, jumpers, config
  * settings, restrictions, cables, device names and numbers in
- * Documentation/specialix.txt
+ * Documentation/serial/specialix.txt
  */
 
 #include <linux/module.h>