mt76: testmode: add a new state for continuous tx

Support to set a special tx state in testmode: continuous tx,
which is used for sending tx without time gap.
Note that continuous tx mode doesn't send real packets, instead, it's
pure phy signal, and the waveform can be observed by instrument.

Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/testmode.h

@@ -143,12 +143,14 @@ enum mt76_testmode_rx_attr {
  * @MT76_TM_STATE_IDLE: test mode enabled, but idle
  * @MT76_TM_STATE_TX_FRAMES: send a fixed number of test frames
  * @MT76_TM_STATE_RX_FRAMES: receive packets and keep statistics
+ * @MT76_TM_STATE_TX_CONT: waveform tx without time gap
  */
 enum mt76_testmode_state {
 	MT76_TM_STATE_OFF,
 	MT76_TM_STATE_IDLE,
 	MT76_TM_STATE_TX_FRAMES,
 	MT76_TM_STATE_RX_FRAMES,
+	MT76_TM_STATE_TX_CONT,
 
 	/* keep last */
 	NUM_MT76_TM_STATES,