scheduler: refine runqueue related functions

add struct sched_object, and use it as input param instead of vcpu for
below functions:
- add_to_cpu_runqueue renamed from add_vcpu_to_runqueue
- remove_from_cpu_runqueue renamed from remove_vcpu_from_runqueue
- get_next_sched_obj added to get next sched object

Tracked-On: #1842
Signed-off-by: Jason Chen CJ <jason.cj.chen@intel.com>
Acked-by: Eddie Dong <edide.dong@intel.com>

hypervisor/include/arch/x86/guest/vcpu.h

@@ -264,7 +264,7 @@ struct acrn_vcpu {
 	volatile enum vcpu_state dbg_req_state;
 	uint64_t sync;	/*hold the bit events*/
 
-	struct list_head run_list; /* inserted to schedule runqueue */
+	struct sched_object sched_obj;
 	uint64_t pending_pre_work; /* any pre work pending? */
 	bool launched; /* Whether the vcpu is launched on target pcpu */
 	uint32_t paused_cnt; /* how many times vcpu is paused */

hypervisor/include/arch/x86/hv_arch.h

@@ -18,6 +18,7 @@
 #include <vmtrr.h>
 #include <timer.h>
 #include <vlapic.h>
+#include <schedule.h>
 #include <vcpu.h>
 #include <trusty.h>
 #include <guest_pm.h>