Populate Protocol property in Item.Drive interface

By populating this property, bmcweb can populate the "Protocol"
property in the Drive schema.

Tested:
$ busctl get-property xyz.openbmc_project.eStoraged \
  /xyz/openbmc_project/inventory/storage/mmcblk0 \
  xyz.openbmc_project.Inventory.Item.Drive Protocol
s "xyz.openbmc_project.Inventory.Item.Drive.DriveProtocol.eMMC"

Signed-off-by: John Wedig <johnwedig@google.com>
Change-Id: I2bd19190c445ce57f3d867ffbb437c1a4a370b51
diff --git a/include/util.hpp b/include/util.hpp
index 7cc778a..e1050ed 100644
--- a/include/util.hpp
+++ b/include/util.hpp
@@ -19,15 +19,17 @@
     uint64_t eraseMaxGeometry;
     uint64_t eraseMinGeometry;
     std::string driveType;
+    std::string driveProtocol;
 
     DeviceInfo(std::filesystem::path& deviceFile,
                std::filesystem::path& sysfsDir, std::string& luksName,
                std::string& locationCode, uint64_t eraseMaxGeometry,
-               uint64_t eraseMinGeometry, std::string& driveType) :
+               uint64_t eraseMinGeometry, std::string& driveType,
+               std::string& driveProtocol) :
         deviceFile(deviceFile),
         sysfsDir(sysfsDir), luksName(luksName), locationCode(locationCode),
         eraseMaxGeometry(eraseMaxGeometry), eraseMinGeometry(eraseMinGeometry),
-        driveType(driveType)
+        driveType(driveType), driveProtocol(driveProtocol)
     {}
 };