Fix vndk snapshot suffix on Makefile

When exporting Soong modules to Makefile, each VNDK snapshot module
whose version is BOARD_VNDK_VERSION has ".vendor" suffix. So makeLibName
should also return ".vendor", not the full vndk snapshot suffix like
".vndk.29.arm64.vendor".

Bug: 151274994
Test: manual build with snapshot
Change-Id: I48f606f90f6c5ca55d0a5bc29bad491c38a44f47
diff --git a/cc/cc.go b/cc/cc.go
index 8b3c772..8d098c8 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -2404,8 +2404,13 @@
 
 			if c, ok := ccDep.(*Module); ok {
 				// Use base module name for snapshots when exporting to Makefile.
-				if c.isSnapshotPrebuilt() && !c.IsVndk() {
+				if c.isSnapshotPrebuilt() {
 					baseName := c.BaseModuleName()
+
+					if c.IsVndk() {
+						return baseName + ".vendor"
+					}
+
 					if vendorSuffixModules[baseName] {
 						return baseName + ".vendor"
 					} else {