compat-drivers: do not call make clean for unified drivers

We can skip the make clean process for unified drivers given
that the script that makes compat-drivers releases, gen-releases.sh,
already ensures that we call $(git clean -f -x -d) on each git
tree we are cherry picking code from.

Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
compat-drivers: fix driver-select for atheros drivers

The addition of the new wil6210 driver added a new ATH_CARDS
option to be used to describe Atheros cards and now uses ATH_COMMON
for the common module ath. This requires fixing the driver-select
script so that the drivers are enabled properly.

Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>