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/config.go b/android/config.go
index cfbc37f..80651bb 100644
--- a/android/config.go
+++ b/android/config.go
@@ -1498,6 +1498,10 @@
 	return c.config.productVariables.BuildBrokenTrebleSyspropNeverallow
 }
 
+func (c *deviceConfig) BuildDebugfsRestrictionsEnabled() bool {
+	return c.config.productVariables.BuildDebugfsRestrictionsEnabled
+}
+
 func (c *deviceConfig) BuildBrokenVendorPropertyNamespace() bool {
 	return c.config.productVariables.BuildBrokenVendorPropertyNamespace
 }