obmc-phosphor-image: enable read-only-rootfs if obmc-ubi-fs enabled

Change-Id: I94fe5ce5231a2950dba5efbb3ee55522da6641a5
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/meta-phosphor/classes/obmc-phosphor-image.bbclass b/meta-phosphor/classes/obmc-phosphor-image.bbclass
index 9b0a547..29694e7 100644
--- a/meta-phosphor/classes/obmc-phosphor-image.bbclass
+++ b/meta-phosphor/classes/obmc-phosphor-image.bbclass
@@ -78,6 +78,7 @@
         obmc-debug-collector \
         obmc-network-mgmt \
         obmc-settings \
+        ${@mf_enabled(d, 'obmc-ubi-fs', 'read-only-rootfs')} \
         "
 
 CORE_IMAGE_EXTRA_INSTALL_append = " bash \