cli: syscall return value check is wrong

ret is uintptr and always >= 0. errno is enough for error checking.
This is causing lint error:
/home/vagrant/workplace/golang/src/github.com/kata-containers/runtime/virtcontainers/utils
cli/kata-check.go:446:20: SA4003: no value of type uintptr is less than 0 (staticcheck)
                if errno != 0 || ret <= 0 {
                                 ^

Signed-off-by: Peng Tao <bergwolf@hyper.sh>

cli/kata-check.go

@@ -443,7 +443,7 @@ func genericCheckKVMExtensions(extensions map[string]kvmExtension) (map[string]i
 
 		// Generally return value(ret) 0 means no and 1 means yes,
 		// but some extensions may report additional information in the integer return value.
-		if errno != 0 || ret <= 0 {
+		if errno != 0 {
 			kataLog.WithFields(fields).Error("is not supported")
 			return results, errno
 		}