mcs: add api method for SC consumed

This adds an API method for calling the seL4_SchedContext_Consumed
operation regardless of whether the CONFIG_KERNEL_MCS is set.
diff --git a/libsel4utils/include/sel4utils/mcs_api.h b/libsel4utils/include/sel4utils/mcs_api.h
index c79388c..1ce3186 100644
--- a/libsel4utils/include/sel4utils/mcs_api.h
+++ b/libsel4utils/include/sel4utils/mcs_api.h
@@ -170,6 +170,18 @@
 #endif
 }
 
+static inline seL4_SchedContext_Consumed_t api_sc_consumed(UNUSED seL4_CPtr sc)
+{
+    if (!config_set(CONFIG_KERNEL_MCS)) {
+        return (seL4_SchedContext_Consumed_t) {
+            .error = (seL4_Error) - ENOSYS
+        };
+    }
+#ifdef CONFIG_KERNEL_MCS
+    return seL4_SchedContext_Consumed(sc);
+#endif
+}
+
 static inline seL4_Error api_sched_ctrl_configure(UNUSED seL4_CPtr sched_ctrl, UNUSED seL4_CPtr sc,
                                                   UNUSED uint64_t budget, UNUSED uint64_t period,
                                                   UNUSED seL4_Word refills, UNUSED seL4_Word badge)