filesystem: mount rw and overlay

Append base-files to add new fstab and depend on mount-overlay recipe.
Add systemd services to help mounting overlay fs.

Resolves openbmc/openbmc#2134

Change-Id: Ib56fcdde9f7364fca56a08e1ce72e7cafaac35b0
Signed-off-by: Edward A. James <eajames@us.ibm.com>
diff --git a/common/recipes-phosphor/mount-overlay-help/mount-overlay-help.bb b/common/recipes-phosphor/mount-overlay-help/mount-overlay-help.bb
new file mode 100644
index 0000000..4125fd0
--- /dev/null
+++ b/common/recipes-phosphor/mount-overlay-help/mount-overlay-help.bb
@@ -0,0 +1,5 @@
+inherit obmc-phosphor-license
+
+SYSTEMD_SERVICE_${PN} = "prepare-overlay.service mount-machine-id.service"
+
+inherit obmc-phosphor-systemd