X.509: Move the trust validation code out to its own file

Move the X.509 trust validation code out to its own file so that it can be
generalised.

Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile
index f904862..6516855 100644
--- a/crypto/asymmetric_keys/Makefile
+++ b/crypto/asymmetric_keys/Makefile
@@ -4,7 +4,10 @@
 
 obj-$(CONFIG_ASYMMETRIC_KEY_TYPE) += asymmetric_keys.o
 
-asymmetric_keys-y := asymmetric_type.o signature.o
+asymmetric_keys-y := \
+	asymmetric_type.o \
+	restrict.o \
+	signature.o
 
 obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += public_key.o