Add devmem to busybox config.
diff --git a/meta-phosphor/common/recipes-core/busybox/busybox_%.bbappend b/meta-phosphor/common/recipes-core/busybox/busybox_%.bbappend
new file mode 100644
index 0000000..225f17a
--- /dev/null
+++ b/meta-phosphor/common/recipes-core/busybox/busybox_%.bbappend
@@ -0,0 +1,2 @@
+FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+SRC_URI += "file://busybox.cfg"