tools: cert_create: Create only requested certificates

The certification tool creates all the certificates mentioned
statically in the code rather than taking explicit certificate
requests from the command line parameters.

Code is optimized to avoid unnecessary attempts to create
non-requested certificates.

Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Change-Id: I78feac25bc701bf8f08c6aa5a2e1590bec92d0f2
diff --git a/tools/cert_create/src/main.c b/tools/cert_create/src/main.c
index d5abe49..8a53377 100644
--- a/tools/cert_create/src/main.c
+++ b/tools/cert_create/src/main.c
@@ -473,6 +473,11 @@
 
 		cert = &certs[i];
 
+		if (cert->fn == NULL) {
+			/* Certificate not requested. Skip to the next one */
+			continue;
+		}
+
 		/* Create a new stack of extensions. This stack will be used
 		 * to create the certificate */
 		CHECK_NULL(sk, sk_X509_EXTENSION_new_null());
@@ -534,7 +539,7 @@
 		}
 
 		/* Create certificate. Signed with corresponding key */
-		if (cert->fn && !cert_new(hash_alg, cert, VAL_DAYS, 0, sk)) {
+		if (!cert_new(hash_alg, cert, VAL_DAYS, 0, sk)) {
 			ERROR("Cannot create %s\n", cert->cn);
 			exit(1);
 		}