CryptoPkg: fix AARCH64 build under CLANG35

CryptoPkg: fix AARCH64 build under CLANG35

The OpenSSL function sk_X509_delete_ptr() resolves through preprocessor
substitution to '(X509 *)sk_delete_ptr()', in which the cast causes the
call to be interpreted as an expression (whose value is not used) rather
than a statement, resulting in the following error under Clang:

  ...: error: expression result unused [-Werror,-Wunused-value]

Add (VOID) casts to silence the error.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Qin Long <qin.long@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18730 6f19259b-4bc3-4df7-8a09-765794883524