Autogenerate a soong module to build odm.img

Test: With https://r.android.com/3326400, notice files are the only
diffs for AOSP CF odm.img
Bug: 376755916

Change-Id: I847f0dc8317d9693de39fed19aeac4e7f8a70152
diff --git a/android/variable.go b/android/variable.go
index a386473..4cdf5fb 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -341,6 +341,7 @@
 	VendorPath           *string `json:",omitempty"`
 	BuildingVendorImage  *bool   `json:",omitempty"`
 	OdmPath              *string `json:",omitempty"`
+	BuildingOdmImage     *bool   `json:",omitempty"`
 	ProductPath          *string `json:",omitempty"`
 	BuildingProductImage *bool   `json:",omitempty"`
 	SystemExtPath        *string `json:",omitempty"`