Build vendor/odm sepolicies with Android.bp

The following files are built with Android.bp:
- vendor_sepolicy.cil
- odm_sepolicy.cil
- prebuilt_sepolicy

Also, prebuilt_policy.mk is removed as it's now redundant.

Bug: 33691272
Test: build and compare artifacts
Test: build with rvc-dev sepolicy
Change-Id: I7bf79c9c85c63cd942b36f7cf5ddda1860626c0b
diff --git a/build/soong/versioned_policy.go b/build/soong/versioned_policy.go
index d4bdd74..dc07910 100644
--- a/build/soong/versioned_policy.go
+++ b/build/soong/versioned_policy.go
@@ -35,8 +35,8 @@
 	// Output file name. Defaults to {name} if target_policy is set, {version}.cil if mapping is set
 	Stem *string
 
-	// Target sepolicy version. Can be a specific version number (e.g. "30.0" for R) or "current"
-	// (PLATFORM_SEPOLICY_VERSION). Defaults to "current"
+	// Target sepolicy version. Can be a specific version number (e.g. "30.0" for R), "current"
+	// (PLATFORM_SEPOLICY_VERSION), or "vendor" (BOARD_SEPOLICY_VERS). Defaults to "current"
 	Version *string
 
 	// If true, generate mapping file from given base cil file. Cannot be set with target_policy.
@@ -90,6 +90,8 @@
 	version := proptools.StringDefault(m.properties.Version, "current")
 	if version == "current" {
 		version = ctx.DeviceConfig().PlatformSepolicyVersion()
+	} else if version == "vendor" {
+		version = ctx.DeviceConfig().BoardSepolicyVers()
 	}
 
 	var stem string