[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>

libcpu/Kconfig

@@ -262,6 +262,15 @@ config ARCH_RISCV64
     select ARCH_CPU_64BIT
     bool
 
+if ARCH_RISCV64
+    config ARCH_USING_RISCV_COMMON64
+        bool
+        depends on ARCH_RISCV64
+        select RT_USING_CPUTIME
+        help
+            Using the common64 implementation under ./libcpu/risc-v
+endif
+
 config ARCH_REMAP_KERNEL
     bool
     depends on RT_USING_SMART