dsp: Reset ec ref port id after use

Reset ec ref port id to invalid port after use to ensure
it is not picked for other adm sessions.

Change-Id: I802326122ad6dc63c7f2df16169da3f50559202f
Signed-off-by: Chaithanya Krishna Bacharaju <chaithan@codeaurora.org>
diff --git a/dsp/q6adm.c b/dsp/q6adm.c
index a265b7b..1723bb2 100644
--- a/dsp/q6adm.c
+++ b/dsp/q6adm.c
@@ -3099,6 +3099,7 @@
 				if (this_adm.num_ec_ref_rx_chans != 0) {
 					open_v8.endpoint_id_2 =
 						this_adm.ec_ref_rx;
+					this_adm.ec_ref_rx = AFE_PORT_INVALID;
 				} else {
 					pr_err("%s: EC channels not set %d\n",
 						__func__,