drivers/e1000: Fix unintended fallthrough

Not desired here according ancient git logs.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

kernel/drivers/net/drivers/e1000/e1000_main.c

@@ -396,6 +396,7 @@ e1000_release_hw_control(struct e1000_adapter *adapter)
 		swsm = E1000_READ_REG(&adapter->hw, SWSM);
 		E1000_WRITE_REG(&adapter->hw, SWSM,
 				swsm & ~E1000_SWSM_DRV_LOAD);
+		break;
 	case e1000_ich8lan:
 		extcnf = E1000_READ_REG(&adapter->hw, CTRL_EXT);
 		E1000_WRITE_REG(&adapter->hw, CTRL_EXT,