Broken build with disabling OpenSSL crypto

Hi everyone!

Commit cb9faa6f98ae ("tools: Use a single target-independent config to enable OpenSSL") recently introduced option to disable usage of OpenSSL via CONFIG_TOOLS_LIBCRYPTO. However, just a bit later, another commit b4f3cc2c42d9 ("tools: kwbimage: Do not hide usage of secure header under CONFIG_ARMADA_38X") made U-Boot tools hard dependent on OpenSSL. That totally defeats the purpose of first commit. I suggest that it gets reverted.

I would like disable OpenSSL for my usage, since it gives me troubles when cross-compiling U-Boot inside LibreELEC build system. It's not needed for our case anyway.

Best regards, Jernej