improved whatsminer handling, and added VF20 to miner dict

miners/whatsminer/btminer/M2X/M21S.py

@@ -2,6 +2,12 @@ from miners._backends import BTMiner  # noqa - Ignore access to _module
 from miners._types import M21SV20, M21SV60  # noqa - Ignore access to _module
 
 
+class BTMinerM21S(BTMiner, M21S):
+    def __init__(self, ip: str) -> None:
+        super().__init__(ip)
+        self.ip = ip
+
+
 class BTMinerM21SV20(BTMiner, M21SV20):
     def __init__(self, ip: str) -> None:
         super().__init__(ip)