[PATCH v0] audio: Fix crash on gateway close

From: Mikel Astiz <redacted>

gateway_close() can be called multiple times and thus the code must
handle the case where device->gateway is already NULL.

This issue can be easily reproduced if a device is removed (unpaired)
while HFP gateway is connected.
---
 audio/gateway.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/audio/gateway.c b/audio/gateway.c
index 45b25a1..93a70ba 100644
--- a/audio/gateway.c
+++ b/audio/gateway.c

@@ -566,6 +566,9 @@ int gateway_close(struct audio_device *device)
 	struct gateway *gw = device->gateway;
 	int sock;
 
+	if (gw == NULL)
+		return 0;
+
 	if (gw->rfcomm) {
 		sock = g_io_channel_unix_get_fd(gw->rfcomm);
 		shutdown(sock, SHUT_RDWR);

-- 
1.7.7.6