Add support for /product-services partition

This is an adaptation of Icc4f8c16bc389fe20db680849f311d02df1299c3, to
support modules that are installed on the /product-services partition.

Bug: 80741439
Test: m -j both with and without enabling the new partition
Change-Id: I72b335ad38baff5848cd3da7489343f8cf98ff16
diff --git a/android/variable.go b/android/variable.go
index 5edcdbc..d97fc0b 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -182,9 +182,10 @@
 	CFIExcludePaths *[]string `json:",omitempty"`
 	CFIIncludePaths *[]string `json:",omitempty"`
 
-	VendorPath  *string `json:",omitempty"`
-	OdmPath     *string `json:",omitempty"`
-	ProductPath *string `json:",omitempty"`
+	VendorPath          *string `json:",omitempty"`
+	OdmPath             *string `json:",omitempty"`
+	ProductPath         *string `json:",omitempty"`
+	ProductServicesPath *string `json:",omitempty"`
 
 	UseClangLld *bool `json:",omitempty"`