fs: Remove duplicated flag O_NDELAY occurring twice in VALID_OPEN_FLAGS

The O_NDELAY flag occurs twice in the VALID_OPEN_FLAGS definition, this
change removes the duplicate.  There is no change to the functionality.

Note, that the flags O_NONBLOCK and O_NDELAY are not duplicates, as
values of these flags are platform dependent, and on platforms like
Sparc O_NONBLOCK and O_NDELAY are not the same.

This has been done that way to maintain the ABI compatibility with
Solaris since the Sparc port was first introduced.

This change resolves the following Coccinelle warning:

  include/linux/fcntl.h:11:13-21: duplicated argument to & or |

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