Report OEMCrypto security patch level

[ Merge of http://go/wvgerrit/17959 ]

This will allow the license server to base licensing decisions on the
devices security module revision.

b/28882058

Change-Id: I574e7686bb305397946d2bfaff504cfae242e628

libwvdrmengine/cdm/core/include/crypto_session.h

@@ -35,6 +35,7 @@ class CryptoSession {
   virtual bool GetApiVersion(uint32_t* version);
   virtual bool GetSystemId(uint32_t* system_id);
   virtual bool GetProvisioningId(std::string* provisioning_id);
+  virtual uint8_t GetSecurityPatchLevel();
 
   virtual CdmResponseType Open() { return Open(kLevelDefault); }
   virtual CdmResponseType Open(SecurityLevel requested_security_level);