util: add i2c->pcie map build method

Move method to util that handles creating a mapping between i2c-bus
numbers and their pci-e slot names.  It's done as a list of tuples.

Tested: Only ran unit-tests.
Change-Id: Ie09d193add63245eebcf3806255311232a7c4c9a
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/util.hpp b/util.hpp
index 760a1b2..d8c8bbd 100644
--- a/util.hpp
+++ b/util.hpp
@@ -1,7 +1,10 @@
 #pragma once
 
+#include <cstdint>
 #include <nlohmann/json.hpp>
 #include <string>
+#include <tuple>
+#include <vector>
 
 namespace google
 {
@@ -25,5 +28,12 @@
  */
 std::string readPropertyFile(const std::string& fileName);
 
+/**
+ * Build a map of the i2c bus numbers to their PCIe slot names.
+ *
+ * @return list of pairs of i2c bus with their corresponding slot names.
+ */
+std::vector<std::tuple<std::uint32_t, std::string>> buildPcieMap();
+
 } // namespace ipmi
 } // namespace google