tools headers UAPI: Sync asm-generic/unistd.h with the kernel original

To pick the changes in:

  8b1462b6 ("quota: finish disable quotactl_path syscall")

Those headers are used in some arches to generate the syscall table used
in 'perf trace' to translate syscall numbers into strings.

This addresses this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/asm-generic/unistd.h' differs from latest version at 'include/uapi/asm-generic/unistd.h'
  diff -u tools/include/uapi/asm-generic/unistd.h include/uapi/asm-generic/unistd.h

Cc: Jan Kara <jack@suse.cz>
Cc: Marcin Juszkiewicz <marcin@juszkiewicz.com.pl>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>