fix check on RSA key size

wolfcrypt/src/error.c

@@ -377,6 +377,9 @@ const char* wc_GetErrorString(int error)
     case WC_PENDING_E:
         return "wolfCrypt Operation Pending (would block / eagain) error";
 
+    case WC_KEY_SIZE_E:
+        return "Key size error, either too small or large";
+
     default:
         return "unknown error number";