[englishbreakfast] Fix paths to delete before running topgen
[englishbreakfast] Fix paths to delete before running topgen

Somehow these paths got out of sync, i.e, they weren't actually deleted
anymore when running the script. In addtion, this commit adds a new
argument to only delete the auto-gen files. Is is useful when switching
back to Earlgrey after having worked with Englishbreakfast.

Signed-off-by: Pirmin Vogel <386a7fc8e7338ed7899b4d9883c0ebec5de81366@lowrisc.org>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan