Add sample systemd unit file Bios upgrade

This is a sample systemd unit file, user should provide platform
specific systemd unit file which executes flash commands.

Signed-off-by: Vijay Khemka <vijaykhemka@fb.com>
Change-Id: I1fd6836e336b6c543647ff2e3e96ad21dc0cb475
diff --git a/Makefile.am b/Makefile.am
index a93ebc8..293867e 100755
--- a/Makefile.am
+++ b/Makefile.am
@@ -54,6 +54,10 @@
 	xyz.openbmc_project.Software.Sync.service \
 	xyz.openbmc_project.Software.Version.service
 
+if HOST_BIOS_UPGRADE
+systemdsystemunit_DATA += obmc-flash-host-bios@.service
+endif
+
 tmpfilesdir=${exec_prefix}/lib/tmpfiles.d/
 dist_tmpfiles_DATA = \
 	software.conf