tools headers: Sync uapi/linux/fcntl.h with the kernel sources

To pick up the changes in this cset:

  e83f0b5 ("nsfs: support exhaustive file handles")

That doesn't introduce anything of interest for tools/, just addresses
these perf build warnings:

Warning: Kernel ABI header differences:
  diff -u tools/perf/trace/beauty/include/uapi/linux/fcntl.h include/uapi/linux/fcntl.h

Please see tools/include/uapi/README for further details.

Cc: Christian Brauner <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: acmel

tools/perf/trace/beauty/include/uapi/linux/fcntl.h

@@ -111,6 +111,7 @@
 #define PIDFD_SELF_THREAD_GROUP		-10001 /* Current thread group leader. */
 
 #define FD_PIDFS_ROOT			-10002 /* Root of the pidfs filesystem */
+#define FD_NSFS_ROOT			-10003 /* Root of the nsfs filesystem */
 #define FD_INVALID			-10009 /* Invalid file descriptor: -10000 - EBADF = -10009 */
 
 /* Generic flags for the *at(2) family of syscalls. */