import-trace: initialize all members

This was never a real problem, but keeps us on the safe side.  Found
by Coverity Scan, CID 25731/25808/25817.

Change-Id: Ie4bd9fb52ff6140ce7ae024738b43c82f6f5045c

tools/import-trace/RegisterImporter.hpp

@@ -25,7 +25,7 @@ class RegisterImporter : public Importer {
 
 public:
 	RegisterImporter() : Importer(), do_gp(true), do_flags(false), do_ip(false),
-						 do_split_registers(true) {}
+						 do_split_registers(true), m_ip_register_id(0) {}
 	/**
 	 * Callback function that can be used to add command line options
 	 * to the cmd interface