libc: Import strtok_r from FreeBSD project

From commit: 21571b1d140ae7bb44e94c0afba2ec61456b275b
Made small changes to fit into TF-A project

Change-Id: I991f653a7ace04f9c84bcda78ad8d7114ea18e93
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
2 files changed