pci: add region parameter to constructor

Add region parameter to constructor for PCI handler so that it knows
what value to send the host when requested.

Change-Id: Iefe1302aaaa43819f84b9730d01ff61dd545e2ef
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/pci_handler.cpp b/pci_handler.cpp
index dce1098..4937742 100644
--- a/pci_handler.cpp
+++ b/pci_handler.cpp
@@ -38,7 +38,7 @@
 {
     /* PCI handler does require returning a configuration from read. */
     struct PciConfigResponse reply;
-    reply.address = 0;
+    reply.address = regionAddress;
 
     std::vector<std::uint8_t> bytes;
     bytes.resize(sizeof(reply));