add esmi repo as git sub module

esmi library repo from gerrit path is added as submodule
to amd-smi repo.
To get esmi submodule synced along with amd-smi repo, cloning can be done with
"git clone --recurse-submodules" or
after cloning amd-smi repo,
"git submodule update --init" will sync the esmi library.

Change-Id: Ia0f382995f29018b469083b27918effc96a51b56

.gitmodules

@@ -0,0 +1,4 @@
+[submodule "e_smi_library"]
+	path = e_smi_library
+	url = ssh://gerritgit/SYS-MGMT/er/HPC/e_smi_library
+	branch = amd-dev