hidl-gen: Allow importing only one type from another hal.

Test: `mma`
Test: hidl_test

Bug: 31821285
Change-Id: I14f069f4a21c71bb85465b77200cc860b84f61ec
diff --git a/FQName.cpp b/FQName.cpp
index 9bc271b..0169e0c 100644
--- a/FQName.cpp
+++ b/FQName.cpp
@@ -241,6 +241,10 @@
     return mName.substr(1);
 }
 
+FQName FQName::getTypesForPackage() const {
+    return FQName(package(), version(), "types");
+}
+
 const FQName FQName::getTopLevelType() const {
     auto idx = mName.find('.');