tools uapi asm-generic: Sync unistd.h with the kernel sources

tools uapi asm-generic: Sync unistd.h with the kernel sources

To pick the change from:

  782ecbfa7687 ("ipc: fix semtimedop for generic 32-bit architectures")

Which doesn't trigger any change in tooling and silences 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: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-hpnjuyjzoudltqe7dvbokqdt@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>