cros-ec: Log error paths, and trigger flushes
cros-ec: Log error paths, and trigger flushes

In case of a failure during the bulk transfer sequence, flush out
before trying again.

hughsie/fwupd,fwupd/fwupd,hughsie/fwupd,fwupd/fwupd,hughsie/fwupd,fwupd/fwupd,hughsie/fwupd,fwupd/fwupd