bury SEL_{IN,OUT,EX}

Had not been used for more than a decade and half; it used
to be a part of (in-kernel) ->select() API and it has been pining
for fjords since 2.1.23pre1.  This is an ex-parrot...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

include/linux/fs.h

@@ -131,10 +131,6 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
  */
 #define CHECK_IOVEC_ONLY -1
 
-#define SEL_IN		1
-#define SEL_OUT		2
-#define SEL_EX		4
-
 /*
  * The below are the various read and write types that we support. Some of
  * them include behavioral modifiers that send information down to the