hypervisor: mshv: implement get_guest_debug_hw_bps

Implement get_guest_debug_hw_bps() for mshv and simply return 0 for now.
This unblocks the usage of the crashdump feature with mshv. If left
unimplemented, Cloud Hypervisor built with mshv and guest_debug features
crashes immediately upon start due to unimplemented!() macro.

Signed-off-by: Anirudh Rayabharam <anrayabh@microsoft.com>

hypervisor/src/mshv/mod.rs

@@ -403,6 +403,10 @@ impl hypervisor::Hypervisor for MshvHypervisor {
         // but the ioctl API is limited to u8
         256
     }
+
+    fn get_guest_debug_hw_bps(&self) -> usize {
+        0
+    }
 }
 
 /// Vcpu struct for Microsoft Hypervisor