hardware interface: add copyFrom

Add a copyFrom method to the hardware window interface and empty
implementations of it within the current lpc handlers.

Change-Id: If2ab6a47763387721edd1a0c451ed8c6087eb475
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/lpc_nuvoton.cpp b/lpc_nuvoton.cpp
index ce0cf30..ebc210c 100644
--- a/lpc_nuvoton.cpp
+++ b/lpc_nuvoton.cpp
@@ -129,4 +129,10 @@
     return std::make_pair(windowOffset, windowSize);
 }
 
+std::vector<std::uint8_t> LpcMapperNuvoton::copyFrom(std::uint32_t length)
+{
+    /* TODO: implement. */
+    return {};
+}
+
 } // namespace blobs