Remove unused state field mask for handling state

serial_substates.h

@@ -18,7 +18,6 @@ enum SerialComm::States : uint8_t {
     AUX_CHAN_MASK,
     COMMANDS,
     F_AND_T,
-    UNUSED,
     PID_FZ_MASTER,
     PID_TX_MASTER,
     PID_TY_MASTER,
@@ -35,6 +34,8 @@ enum SerialComm::States : uint8_t {
     END_OF_STATES,
 };
 
+static_assert(SerialComm::States::END_OF_STATES == 27, "Added/removed states not acknowledged");
+
 // Reads part of the state into a COBS payload, named "payload"
 #define READ_SUBSTATE(name) \
     template <>             \
@@ -71,9 +72,6 @@ READ_SUBSTATE_PAYLOAD(AUX_CHAN_MASK, state->command_AUX_mask)
 READ_SUBSTATE_PAYLOAD(COMMANDS, state->command_throttle, state->command_pitch, state->command_roll, state->command_yaw)
 READ_SUBSTATE_PAYLOAD(F_AND_T, state->Fz, state->Tx, state->Ty, state->Tz)
 
-READ_SUBSTATE(UNUSED) {
-}
-
 READ_SUBSTATE(PID_FZ_MASTER) {
     WritePIDData(payload, control->thrust_pid.master());
 }