fuzz: exercise fido_cred_{,set_}entattest()

Use excl_cred's first byte as an input to fido_cred_set_entattest();
like what fido_cred_set_prot() is doing with user_id. This saves adding
additional members to the parameter struct.

fuzz/export.gnu

@@ -127,6 +127,7 @@
 		fido_cred_clientdata_hash_len;
 		fido_cred_clientdata_hash_ptr;
 		fido_cred_display_name;
+		fido_cred_entattset;
 		fido_cred_exclude;
 		fido_cred_flags;
 		fido_cred_largeblob_key_len;
@@ -172,6 +173,7 @@
 		fido_cred_set_blob;
 		fido_cred_set_clientdata;
 		fido_cred_set_clientdata_hash;
+		fido_cred_set_entattest;
 		fido_cred_set_extensions;
 		fido_cred_set_fmt;
 		fido_cred_set_id;

fuzz/fuzz_cred.c

@@ -248,6 +248,8 @@ make_cred(fido_cred_t *cred, uint8_t opt, int type, const struct blob *cdh,
 		fido_cred_set_uv(cred, FIDO_OPT_TRUE);
 	if (user_id->len)
 		fido_cred_set_prot(cred, user_id->body[0] & 0x03);
+	if (excl_cred->len)
+		fido_cred_set_entattest(cred, excl_cred->body[0] & 0x03);
 
 	/* repeat memory operations to trigger reallocation paths */
 	fido_cred_set_type(cred, type);
@@ -279,6 +281,7 @@ verify_cred(int type, const unsigned char *cdh_ptr, size_t cdh_len,
 	uint8_t flags;
 	uint32_t sigcount;
 	int r;
+	bool ea;
 
 	if ((cred = fido_cred_new()) == NULL)
 		return;
@@ -348,6 +351,9 @@ verify_cred(int type, const unsigned char *cdh_ptr, size_t cdh_len,
 	minpinlen = fido_cred_pin_minlen(cred);
 	consume(&minpinlen, sizeof(minpinlen));
 
+	ea = fido_cred_entattest(cred);
+	consume(&ea, sizeof(ea));
+
 	fido_cred_free(&cred);
 }