gsm29205_test: fix error: missing braces around initializer

Since structure 'osmo_gcr_parsed' does contain arrays, GCC is not
happy about the way we initialize it. Let's do it explicitly.

Change-Id: Ia814b4a4ed5bec84ff1f69232f7f7d5ca0d19794
diff --git a/tests/gsm29205/gsm29205_test.c b/tests/gsm29205/gsm29205_test.c
index 5add1b1..44c3453 100644
--- a/tests/gsm29205/gsm29205_test.c
+++ b/tests/gsm29205/gsm29205_test.c
@@ -44,7 +44,13 @@
 	};
 	uint8_t len;
 	struct msgb *msg;
-	struct osmo_gcr_parsed p = { 0 }, g = {
+	struct osmo_gcr_parsed p = {
+		.net_len = 0,
+		.net = { 0 },
+		.node = 0x00,
+		.cr = { 0 },
+	};
+	struct osmo_gcr_parsed g = {
 		.net_len = 3,
 		.net = { 0x51, 0x52, 0x53 },
 		.node = 0xDEAD,