Correct doxygen syntax in phosphor-net-ipmid

Resolves openbmc/openbmc#1147

Change-Id: I57ab1b09ec1bf308cc3d97cd30b2d18564beb38b
Signed-off-by: Tom Joseph <tomjoseph@in.ibm.com>
diff --git a/command/guid.hpp b/command/guid.hpp
index 03c6272..622b330 100644
--- a/command/guid.hpp
+++ b/command/guid.hpp
@@ -10,7 +10,7 @@
 
 constexpr size_t BMC_GUID_LEN = 16;
 
-/*
+/**
  * @brief Get System GUID
  *
  * @return If UUID is successfully read from the Chassis DBUS object, then the