wolfssl: Avoid conflict with RNG when built without EdDSA or FIPS enabled

wolfssl: Avoid conflict with RNG when built without EdDSA or FIPS enabled

There are definitions of RNG in <wolfssl/wolfcrypt/settings.h> and
<wolfssl/wolfcrypt/random.h> that play havoc with the literal RNG being
used in the expansions of PLUGIN_*(RNG, ...) when ##-concatenated to
build the enum value FEATURE_RNG.

The #undef in wolfssl_cmmon.h only had an effect if wolfSSL was built
with EdDSA or FIPS enabled, otherwise, the headers that define RNG were
not pulled in before it.

Signed-off-by: Philip Prindeville <philipp@redfish-solutions.com>