Deprecate depfile in gensrcs

All existing gensrsc modulePartners who use the property can use BUILD_BROKEN_DEP_FILE to bypass the error

Test: CI
Bug: 179452413
Fix: 179452413
Change-Id: I7cd39484b43eba693d79188b9a374f192198f90f
diff --git a/android/variable.go b/android/variable.go
index 9478c0c..6adb0ac 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -428,6 +428,7 @@
 
 	ShippingApiLevel *string `json:",omitempty"`
 
+	BuildBrokenDepfile                 *bool    `json:",omitempty"`
 	BuildBrokenEnforceSyspropOwner     bool     `json:",omitempty"`
 	BuildBrokenTrebleSyspropNeverallow bool     `json:",omitempty"`
 	BuildBrokenVendorPropertyNamespace bool     `json:",omitempty"`