ipacm: ignore removeDownstream request if netdev down

Simply return sucess to HAL client if receiving the
removeDownstream request when netdev already down

Bug: 34361337
Change-Id: I92ee1713635f23ddb19042b32f2790350591b069
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>

ipacm/src/IPACM_OffloadManager.cpp

diff --git a/ipacm/src/IPACM_OffloadManager.cpp b/ipacm/src/IPACM_OffloadManager.cpp
index 3f16d7c..4ff46c2 100644
--- a/ipacm/src/IPACM_OffloadManager.cpp
+++ b/ipacm/src/IPACM_OffloadManager.cpp
@@ -311,8 +311,8 @@
 
 	if(ipa_get_if_index(downstream_name, &index))
 	{
-		IPACMERR("fail to get iface index.\n");
-		return FAIL_HARDWARE;
+		IPACMERR("netdev(%s) already removed, ignored\n", downstream_name);
+		return SUCCESS;
 	}
 
 	evt_data = (ipacm_event_ipahal_stream*)malloc(sizeof(ipacm_event_ipahal_stream));