qcacmn: Make scheduler context static inside scheduler core

Make scheduler context static such that its not visible outside
core scheduler.

Change-Id: I202cfc62f7ff56f9f7d5a327dfe033f49d6c829e
CRs-Fixed: 1104147

sch/src/scheduler_core.c

@@ -28,7 +28,7 @@
 #include <scheduler_core.h>
 #include <osdep.h>
 
-struct scheduler_ctx *gp_sched_ctx = NULL;
+static struct scheduler_ctx *gp_sched_ctx;
 
 QDF_STATUS scheduler_create_ctx(void)
 {