Fix vendor variants generation of vndk

Current routine to check whether BOARD_VNDK_VERSION variant is created
or not is not correct, because only non-VNDK modules are installed in
/vendor. Thus, BOARD_VNDK_VERSION variants should only be created with
non-VNDK modules.

Bug: N/A
Test: m nothing
Change-Id: I2ee7821fce407214ac6be4f4b6d62483c907971f
diff --git a/cc/cc.go b/cc/cc.go
index a312c49..5dfc563 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -2653,7 +2653,11 @@
 		// or a /system directory that is available to vendor.
 		coreVariantNeeded = true
 		vendorVariants = append(vendorVariants, platformVndkVersion)
-		if m.IsVndk() {
+		// VNDK modules must not create BOARD_VNDK_VERSION variant because its
+		// code is PLATFORM_VNDK_VERSION.
+		// On the other hand, vendor_available modules which are not VNDK should
+		// also build BOARD_VNDK_VERSION because it's installed in /vendor.
+		if !m.IsVndk() {
 			vendorVariants = append(vendorVariants, deviceVndkVersion)
 		}
 	} else if vendorSpecific && String(m.Properties.Sdk_version) == "" {