Clean up MFS a bit:

- Remove unused includes.
 - Add include guards to headers.
 - Use unsigned variables in case they're never going to hold a negative
   value. This causes GCC's complaints to disappear and should make flexelint
   a lot happier, too.
 - Make functions private when they're used only within a module.
 - Remove unused variables.
 - Add casts where appropriate.

servers/vfs/const.h

@@ -32,8 +32,6 @@
 
 #define SYMLOOP		16
 
-#define ROOT_INODE         1		/* inode number for root directory */
-
 #define LABEL_MAX	16	/* maximum label size (including '\0'). Should
 				 * not be smaller than 16 or bigger than
 				 * M3_LONG_STRING.