dsp: don't reset rx ec ref channel after adm open

Remove reset of rx ec ref channel for adm after using,
if the channel value is not changed, user space won't
set it to driver again, then causing adm opening failed.

dsp/q6adm.c

@@ -3278,7 +3278,6 @@ int adm_open(int port_id, int path, int rate, int channel_mode, int topology,
 			if ((this_adm.num_ec_ref_rx_chans != 0)
 				&& (path != ADM_PATH_PLAYBACK)
 				&& (open_v8.endpoint_id_2 != 0xFFFF)) {
-				this_adm.num_ec_ref_rx_chans = 0;
 				memcpy(adm_params + sizeof(open_v8)
 						+ ep1_payload_size,
 						(void *)&ep2_payload,