Add rsa+kw testing support to simulator

Allows simulating images signed with RSA-2048 and encrypted with
AES-128-KW.

Signed-off-by: Fabio Utzig <utzig@apache.org>
diff --git a/sim/src/lib.rs b/sim/src/lib.rs
index 7eb27c5..629b916 100644
--- a/sim/src/lib.rs
+++ b/sim/src/lib.rs
@@ -1183,7 +1183,14 @@
 
 // The TLV in use depends on what kind of signature we are verifying.
 #[cfg(feature = "sig-rsa")]
+#[cfg(feature = "enc-kw")]
+fn make_tlv() -> TlvGen {
+    TlvGen::new_rsa_kw()
+}
+
+#[cfg(feature = "sig-rsa")]
 #[cfg(not(feature = "enc-rsa"))]
+#[cfg(not(feature = "enc-kw"))]
 fn make_tlv() -> TlvGen {
     TlvGen::new_rsa_pss()
 }
@@ -1205,6 +1212,7 @@
     TlvGen::new_sig_enc_rsa()
 }
 
+#[cfg(not(feature = "sig-rsa"))]
 #[cfg(feature = "enc-kw")]
 fn make_tlv() -> TlvGen {
     TlvGen::new_enc_kw()