csp_thread: Fix the comment in samples/arch/main.c
csp_thread is now gone.  Remove the comment.
@@ -41,7 +41,7 @@ int main(int argc, char * argv[]) {
csp_log_protocol("csp_log_protocol(...), level: %d", CSP_PROTOCOL);
csp_log_lock("csp_log_lock(...), level: %d", CSP_LOCK);
- // create a thread - csp_thread doesn't support join
+ // create a thread
k_tid_t tid;
struct k_thread new_thread;
