data handler: add open method

Add open method to data handler object.  The exact purpose of this
method will vary by transport mechanism.

Change-Id: I3d1fa3914e010ac7590455ae3f948a1d9d5cee4b
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/pci_handler.cpp b/pci_handler.cpp
index 852d846..3fa7ec9 100644
--- a/pci_handler.cpp
+++ b/pci_handler.cpp
@@ -7,6 +7,14 @@
 namespace blobs
 {
 
+bool PciDataHandler::open()
+{
+    /* For the ASPEED P2A driver, this method will enable the memory region to
+     * use.
+     */
+    return false;
+}
+
 std::vector<std::uint8_t> PciDataHandler::copyFrom(std::uint32_t length)
 {
     /* TODO: implement this. */