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

android/config.go

@@ -1498,6 +1498,10 @@ func (c *deviceConfig) BuildBrokenTrebleSyspropNeverallow() bool {
 	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
 }