Update matching prompt in common boot template

Earlier, we were using an old kerne and rootfs from 18.09.xx.

We've now switched to using a much newer one from v2020, which is where
it requires an update of our assumpt login prompts

Signed-off-by: Ritesh Raj Sarraf <ritesh.sarraf@collabora.com>

lava/common-boot-tpl.yaml

@@ -75,7 +75,7 @@ actions:
       prompts:
         - 'user@apertis:'
         - '\$ '
-        - '\# '
+        - '/home/user # '
       auto_login:
         login_prompt: 'apertis login:'
         username: user