[libcpu/rv64] feat: unify tick.c

The changes unify the tick.c implementations for all risc-v64
architectures, leveraging the CPUTIME feature. This refactoring was
necessary to streamline the codebase, and ensure consistent timer
handling across different platforms.

Changes:
- Updated `Kconfig` in `bsp/cvitek/cv18xx_risc-v` to fix formatting issues.
- Updated .config for BSPs to update `CPUTIME_TIMER_FREQ`
- Updated header of for API `riscv_cputime_init`
- Initialized riscv timer on `rt_hw_tick_init`
- Refactored `tick.c` and `tick.h` in `libcpu/risc-v/t-head/c906` and `libcpu/risc-v/virt64`:
  - Replaced direct use of `rdtime` with `clock_cpu_gettime`.
  - Removed redundant timer frequency definitions.
  - Added static assertions to check the value of `CPUTIME_TIMER_FREQ`.
  - Initialized `tick_cycles` based on `CPUTIME_TIMER_FREQ`.
  - Integrated `ktime` support for tick initialization.

Signed-off-by: Shell <smokewood@qq.com>
Reviewed-on: https://github.com/RT-Thread/rt-thread/pull/9164
Reviewed-by: Chen Wang <unicorn_wang@outlook.com>

components/drivers/include/drivers/cputime.h

@@ -31,4 +31,8 @@ uint64_t clock_cpu_millisecond(uint64_t cpu_tick);
 
 int clock_cpu_setops(const struct rt_clock_cputime_ops *ops);
 
+#ifdef RT_USING_CPUTIME_RISCV
+int riscv_cputime_init(void);
+#endif /* RT_USING_CPUTIME_RISCV */
+
 #endif