Replace magic for trusting the secondary keyring with #define

Replace the use of a magic number that indicates that verify_*_signature()
should use the secondary keyring with a symbol.

Signed-off-by: Yannik Sembritzki <yannik@sembritzki.me>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: keyrings@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

crypto/asymmetric_keys/pkcs7_key_type.c

@@ -63,7 +63,7 @@ static int pkcs7_preparse(struct key_preparsed_payload *prep)
 
 	return verify_pkcs7_signature(NULL, 0,
 				      prep->data, prep->datalen,
-				      (void *)1UL, usage,
+				      VERIFY_USE_SECONDARY_KEYRING, usage,
 				      pkcs7_view_content, prep);
 }