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/block/floppy.c b/drivers/block/floppy.c
index 14db747..cf29cc4 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4124,7 +4124,7 @@
 		printk("\n");
 	} else
 		DPRINT("botched floppy option\n");
-	DPRINT("Read Documentation/floppy.txt\n");
+	DPRINT("Read Documentation/blockdev/floppy.txt\n");
 	return 0;
 }