Add a variable that indicates build-time debugfs restrictions

This patch adds a variable to indicate to check if the target has the
flag PRODUCT_SET_DEBUGFS_RESTRICTIONS enabled.

Bug: 184381659
Test: make with/without PRODUCT_SET_DEBUGFS_RESTRICTIONS set
Change-Id: Ic14a3759b155ed4e16048d62fcd990f4ba7c906a
diff --git a/android/variable.go b/android/variable.go
index dff48c2..f25143d 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -385,6 +385,8 @@
 	BuildBrokenTrebleSyspropNeverallow bool `json:",omitempty"`
 	BuildBrokenVendorPropertyNamespace bool `json:",omitempty"`
 
+	BuildDebugfsRestrictionsEnabled bool `json:",omitempty"`
+
 	RequiresInsecureExecmemForSwiftshader bool `json:",omitempty"`
 
 	SelinuxIgnoreNeverallows bool `json:",omitempty"`