Add vendor_manifest.xml to createFsGenState

Given that the module cannot be unconditionally added to
PRODUCT_PACKAGES.

Test: m soong_generated_vendor_filesystem_test
Change-Id: Ide8f330a2a94290adb187468e3b5b18938fafe7c
diff --git a/fsgen/fsgen_mutators.go b/fsgen/fsgen_mutators.go
index 9b25e77..f0eea8e 100644
--- a/fsgen/fsgen_mutators.go
+++ b/fsgen/fsgen_mutators.go
@@ -178,6 +178,10 @@
 			(*fsGenState.fsDeps["product"])["system_other_avbpubkey"] = defaultDepCandidateProps(ctx.Config())
 		}
 
+		if len(ctx.Config().DeviceManifestFiles()) > 0 {
+			(*fsGenState.fsDeps["vendor"])["vendor_manifest.xml"] = defaultDepCandidateProps(ctx.Config())
+		}
+
 		// Add common resources `prebuilt_res` module as dep of recovery partition
 		(*fsGenState.fsDeps["recovery"])[fmt.Sprintf("recovery-resources-common-%s", getDpi(ctx))] = defaultDepCandidateProps(ctx.Config())
 		(*fsGenState.fsDeps["recovery"])[getRecoveryFontModuleName(ctx)] = defaultDepCandidateProps(ctx.Config())