Move keymaster test fixture to utils, so we can reuse it.

Change-Id: I7e080326a97712bc1b6810e7231ecf78b7d4e28f
diff --git a/soft_keymaster_device.cpp b/soft_keymaster_device.cpp
index c3ad466..e5c3e5d 100644
--- a/soft_keymaster_device.cpp
+++ b/soft_keymaster_device.cpp
@@ -118,6 +118,10 @@
     return &device_.common;
 }
 
+keymaster1_device_t* SoftKeymasterDevice::keymaster_device() {
+    return &device_;
+}
+
 static keymaster_key_characteristics_t* BuildCharacteristics(const AuthorizationSet& hw_enforced,
                                                              const AuthorizationSet& sw_enforced) {
     keymaster_key_characteristics_t* characteristics =