Build VNDK APEX for VNDK-Lite

For VNDK-Lite devices, which doesn't define BOARD_VNDK_VERSION, VNDK
APEX is built with only VNDK-Sp libraries with core variants.

Bug: 141908078
Bug: 152353068
Bug: 151635128
Test: TH
Change-Id: I0d08d32473368fd158818d4c2c72fc4cfad68ce6
diff --git a/apex/vndk.go b/apex/vndk.go
index f2e913e..2a0d5b0 100644
--- a/apex/vndk.go
+++ b/apex/vndk.go
@@ -95,6 +95,10 @@
 func apexVndkDepsMutator(mctx android.BottomUpMutatorContext) {
 	if m, ok := mctx.Module().(*cc.Module); ok && cc.IsForVndkApex(mctx, m) {
 		vndkVersion := m.VndkVersion()
+		// For VNDK-Lite device, we gather core-variants of VNDK-Sp libraries, which doesn't have VNDK version defined
+		if vndkVersion == "" {
+			vndkVersion = mctx.DeviceConfig().PlatformVndkVersion()
+		}
 		vndkApexList := vndkApexList(mctx.Config())
 		if vndkApex, ok := vndkApexList[vndkVersion]; ok {
 			mctx.AddReverseDependency(mctx.Module(), sharedLibTag, vndkApex)