tests: Avoid passing incompatible arguments to OpenSSL
https://github.com/Yubico/yubico-piv-tool/commit/653ce43556535504d7901a897ef5e96557b374af

--- yubico-piv-tool-2.6.0-origin/ykcs11/tests/ykcs11_tests_util.c
+++ yubico-piv-tool-2.6.0/ykcs11/tests/ykcs11_tests_util.c
@@ -307,7 +307,7 @@
   CK_BYTE     id = 1;
   CK_BYTE     value_c[255] = {0};
   CK_CHAR     pvt[255] = {0};
-  CK_ULONG    pvt_len  = sizeof(pvt);
+  size_t    pvt_len  = sizeof(pvt);
 
 
   CK_ATTRIBUTE privateKeyTemplate[] = {
@@ -375,7 +375,7 @@
   CK_ULONG    kt = CKK_EC_MONTGOMERY;
   CK_BYTE     id = 1;
   CK_CHAR     pvt[255] = {0};
-  CK_ULONG    pvt_len  = sizeof(pvt);
+  size_t    pvt_len  = sizeof(pvt);
 
 
   CK_ATTRIBUTE privateKeyTemplate[] = {
@@ -1731,4 +1731,4 @@
     }
   }
   asrt(found, CK_TRUE, "EXPECTED OBJECT FOUND");
-}
\ No newline at end of file
+}
