meta-facebook: enable allow-root-login

root is only added to a number of required groups if either
`debug-tweaks` or `allow-root-login` is on (see
phosphor-rootfs-postcommands.bbclass).  For internal builds we turn off
`debug-tweaks`, so add `allow-root-login` to our IMAGE_FEATURES since we
need it on everywhere.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ic65dce4fd5374a6a9c8389c67693b980a2b5509c
diff --git a/meta-facebook/conf/machine/include/facebook.inc b/meta-facebook/conf/machine/include/facebook.inc
index 47b641d..c612379 100644
--- a/meta-facebook/conf/machine/include/facebook.inc
+++ b/meta-facebook/conf/machine/include/facebook.inc
@@ -15,6 +15,7 @@
 PREFERRED_PROVIDER_virtual/obmc-system-mgmt = "packagegroup-fb-apps"
 
 IMAGE_FEATURES:remove = "obmc-ikvm"
+IMAGE_FEATURES:append = " allow-root-login"
 
 # Most of our hardware uses the default ttyS4 but at 57600.
 SERIAL_CONSOLES:facebook = "57600;ttyS4"