QuRT: added sched.h

Added the pieces required from sched.h

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/platforms/qurt/include/sched.h

+#pragma once
+
+#define SCHED_FIFO     1
+#define SCHED_RR       2
+
+struct sched_param
+{
+	int sched_priority;
+};
+
+int    sched_get_priority_max(int policy);
+int    sched_get_priority_min(int policy);
+