CLOCK_FREQ is error?

For qemu-system-riscv64, the timebase-frequency is described in dts.
```plain
/ {
    cpus {
        ......
		timebase-frequency = <0x989680>;
        ......
    }
}
```
0x989680 = 10_000_000 = 10Mhz

```rust
/// clock frequency
pub const CLOCK_FREQ: usize = 12500000;
```

But in config.rs, CLOCK_FREQ is defined as 12_500_000 = 12.5Mhz.

Is it an error or designed for something?
