libgloss: kvx-cos: getpid: process id is constant

Summary:
getpid returns a process id on Linux.
Therefore, we return the same id for a single
cluster, and different accross clusters.

Ref T22362

Test Plan: CI

Reviewers: O26 newlib!

Maniphest Tasks: T22362

Differential Revision: https://phab.kalray.eu/D33883

libgloss/kvx-cos/getpid.c

@@ -9,7 +9,9 @@
 int
 _getpid ()
 {
-  return 0x1000 | (__cos_get_cluster_id() << 4) | __cos_get_cpu_id();
+  const int pcid = mppa_cos_get_physical_cluster_id();
+
+  return 0x1000 | (pcid << 4);
 }
 
 int getpid ()