Remove unused condition in decodeSdkDep(...)

The string "core.platform.api.stubs" is never passed to the toModule
function since change I6bb6c1a0ea24437c8253dc5d8fabd37edabc9d3e.

Bug: 134566750
Test: m droid
Change-Id: Ia425a433cd762bba30be72e837fa4199580e5b6c

java/sdk.go

@@ -153,8 +153,6 @@ func decodeSdkDep(ctx android.BaseModuleContext, sdkContext sdkContext) sdkDep {
 
 		if m == "core.current.stubs" {
 			ret.systemModules = "core-current-stubs-system-modules"
-		} else if m == "core.platform.api.stubs" {
-			ret.systemModules = "core-platform-api-stubs-system-modules"
 		}
 		return ret
 	}