crypto: ccp - Rename macro for security attributes

The attribute_show() macro is only valid for determining the availability
of security related sysfs entries. Rename the macro to better show this
relationship.

Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>