vendor: BuildOsVariant > BuildOSTarget

Fixes the following build error:

   vendor/lineage/build/soong/generator/generator.go:125:26: ctx.Config().BuildOsVariant undefined (type android.Config has no field or method BuildOsVariant)

Change-Id: I3385941b2931e5be8010d31f80f3aa033d0d3727
diff --git a/build/soong/generator/generator.go b/build/soong/generator/generator.go
index 7da1fde..a6b2dd1 100644
--- a/build/soong/generator/generator.go
+++ b/build/soong/generator/generator.go
@@ -121,9 +121,8 @@
 	android.ExtractSourcesDeps(ctx, g.properties.Tool_files)
 	if g, ok := ctx.Module().(*Module); ok {
 		if len(g.properties.Tools) > 0 {
-			ctx.AddFarVariationDependencies([]blueprint.Variation{
-				{"arch", ctx.Config().BuildOsVariant},
-			}, hostToolDepTag, g.properties.Tools...)
+			ctx.AddFarVariationDependencies(ctx.Config().BuildOSTarget.Variations(),
+				hostToolDepTag, g.properties.Tools...)
 		}
 	}
 }