[arm64] add hw thread self (#8942)

* [libcpu] arm64: Add hardware thread_self support

This patch introduces hardware-based thread self-identification
for the AArch64 architecture. It optimizes thread management by
using hardware registers to store and access the current thread's
pointer, reducing overhead and improving overall performance.

Changes include:
- Added `ARCH_USING_HW_THREAD_SELF` configuration option.
- Modified `rtdef.h`, `rtsched.h` to conditionally include
  `critical_switch_flag` based on the new config.
- Updated context management in `context_gcc.S`, `cpuport.h`
  to support hardware-based thread self.
- Enhanced `scheduler_mp.c` and `thread.c` to leverage the new
  hardware thread self feature.

These modifications ensure better scheduling and thread handling,
particularly in multi-core environments, by minimizing the
software overhead associated with thread management.

Signed-off-by: Shell <smokewood@qq.com>

* fixup: address suggestion

* fixup: rt_current_thread as global

* scheduler: add cpu object for UP scheduler

Also, maintain the rt_current_thread in cpu object on UP scheduler.

---------

Signed-off-by: Shell <smokewood@qq.com>

include/rtsched.h

@@ -56,6 +56,10 @@ struct rt_sched_thread_ctx
     rt_uint8_t                  sched_flag_locked:1;    /**< calling thread have the scheduler locked */
     rt_uint8_t                  sched_flag_ttmr_set:1;  /**< thread timer is start */
 
+#ifdef ARCH_USING_HW_THREAD_SELF
+    rt_uint8_t                  critical_switch_flag:1; /**< critical switch pending */
+#endif /* ARCH_USING_HW_THREAD_SELF */
+
 #ifdef RT_USING_SMP
     rt_uint8_t                  bind_cpu;               /**< thread is bind to cpu */
     rt_uint8_t                  oncpu;                  /**< process on cpu */
@@ -170,6 +174,7 @@ rt_err_t rt_sched_thread_timer_stop(struct rt_thread *thread);
 rt_err_t rt_sched_thread_timer_start(struct rt_thread *thread);
 void rt_sched_insert_thread(struct rt_thread *thread);
 void rt_sched_remove_thread(struct rt_thread *thread);
+struct rt_thread *rt_sched_thread_self(void);
 
 #endif /* defined(__RT_KERNEL_SOURCE__) || defined(__RT_IPC_SOURCE__) */