revert: replace in-tree Event Log Lib w/ submodule

This reverts commit cc89c2fc40c74ea8d8f1a1489ea988c66c1b5849.

Reason for revert: Causing CI failures

Change-Id: Iad32fb9ba1d32044ef647f01e3091e9b0ee0d9e2
diff --git a/Makefile b/Makefile
index 3ebf566..d5a18be 100644
--- a/Makefile
+++ b/Makefile
@@ -98,6 +98,9 @@
 
 DOCS_PATH		:=	docs
 
+# Path to Transfer List Library (LibTL)
+LIBTL_PATH		:=	contrib/libtl
+
 ifeq (${PLAT},)
   $(error "Error: Unknown platform. Please use PLAT=<platform name> to specify the platform")
 endif