Populate uniq field in uhid.

Sony introduced some logic that combines devices kernel splits into one
Android device based on identical pid, vid and non-empty uniq. Therefore
populate this field with device ID.

We can change that to a separate uniq attribute in register JSON file if
necessary later.

Bug: 38511270
Test: getevent -li shows that uniq is populated.
Change-Id: Ieca0b826c86e9cad7fa3d3c8f98b9cfd54d20c73

cmds/hid/jni/com_android_commands_hid_Device.cpp

@@ -146,6 +146,8 @@ std::unique_ptr<Device> Device::open(int32_t id, const char* name, int32_t vid,
     struct uhid_event ev = {};
     ev.type = UHID_CREATE2;
     strlcpy(reinterpret_cast<char*>(ev.u.create2.name), name, sizeof(ev.u.create2.name));
+    std::string uniq = android::base::StringPrintf("Id: %d", id);
+    strlcpy(reinterpret_cast<char*>(ev.u.create2.uniq), uniq.c_str(), sizeof(ev.u.create2.uniq));
     memcpy(&ev.u.create2.rd_data, descriptor.data(), size * sizeof(ev.u.create2.rd_data[0]));
     ev.u.create2.rd_size = size;
     ev.u.create2.bus = bus;