cc/cc.go: Add Device() method to LinkableInterface

The intention is to make the next change more cherry-pick-friendly.

Bug: 192647618
Test: Presubmit
Change-Id: Ic84d3991a855e09aa9f46e12b759ad8142701e1f
diff --git a/cc/linkable.go b/cc/linkable.go
index 231626e..3760201 100644
--- a/cc/linkable.go
+++ b/cc/linkable.go
@@ -124,6 +124,7 @@
 	IsPrebuilt() bool
 	Toc() android.OptionalPath
 
+	Device() bool
 	Host() bool
 
 	InRamdisk() bool