kata-ctl: Add stub of missing method for ppc

`host_is_vmcontainer_capable` is required, but wasn't
implemented for powerpc64, so copy the aarch64 approach
@Amulyam24

Signed-off-by: stevenhorsman <steven@uk.ibm.com>

src/tools/kata-ctl/src/arch/powerpc64/mod.rs

@@ -31,4 +31,9 @@ mod arch_specific {
         // to get cpu details specific to powerpc architecture similar
         // to the goloang implementation of function getCPUDetails()
     }
+
+    pub fn host_is_vmcontainer_capable() -> Result<bool> {
+        // TODO: Not implemented
+        Ok(true)
+    }
 }