cert_create: remove unneeded initializers

These variables store return values of functions.  Remove all of
meaningless initializers.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/tools/cert_create/src/cert.c b/tools/cert_create/src/cert.c
index a559832..375c66b 100644
--- a/tools/cert_create/src/cert.c
+++ b/tools/cert_create/src/cert.c
@@ -103,10 +103,10 @@
 	cert_t *issuer_cert = &certs[cert->issuer];
 	EVP_PKEY *ikey = keys[issuer_cert->key].key;
 	X509 *issuer = issuer_cert->x;
-	X509 *x = NULL;
-	X509_EXTENSION *ex = NULL;
-	X509_NAME *name = NULL;
-	ASN1_INTEGER *sno = NULL;
+	X509 *x;
+	X509_EXTENSION *ex;
+	X509_NAME *name;
+	ASN1_INTEGER *sno;
 	int i, num;
 
 	/* Create the certificate structure */
@@ -202,7 +202,7 @@
 
 cert_t *cert_get_by_opt(const char *opt)
 {
-	cert_t *cert = NULL;
+	cert_t *cert;
 	unsigned int i;
 
 	for (i = 0; i < num_certs; i++) {