hvf: Suppress hvf build error on RISC-V 64-bit

Signed-off-by: Bingxin Li <[email protected]>

Author: alicedreamed

src/hvf/src/lib.rs

@@ -343,6 +343,8 @@ impl HvfVcpu<'_> {
         };
         #[cfg(target_arch = "x86_64")]
         let cntfrq = 0u64;
+        #[cfg(target_arch = "riscv64")]
+        let cntfrq = 0u64;
 
         let ret = unsafe {
             hv_vcpu_create(