correctly use asn1c API: PDU pointers must be NULL when calling decoder

If the pointers are != NULL, asn1c assumes their memory has already been
allocated, rather than dynamically allocating storage for it.

Change-Id: I6b78be75d8927f032ca4051520a3053b3fbf9e13
diff --git a/src/bankd_main.c b/src/bankd_main.c
index f84d0d0..a2dccea 100644
--- a/src/bankd_main.c
+++ b/src/bankd_main.c
@@ -374,7 +374,7 @@
 	uint8_t buf[65536]; /* maximum length expressed in 16bit length field */
 	asn_dec_rval_t rval;
 	int data_len, rc;
-	RsproPDU_t *pdu;
+	RsproPDU_t *pdu = NULL;
 
 	/* 1) blocking read of entire IPA message from the socket */
 	rc = blocking_ipa_read(worker->client.fd, buf, sizeof(buf));