Important change: make ALSA_CARDS an use-expanded variable, so list all the available...

Important change: make ALSA_CARDS an use-expanded variable, so list all the available drivers during emerge -pv output; the default for all profiles now is to build all drivers (ALSA_CARDS unset), but in the next days proper default subsets will appear on the architecture profiles. Also fix bug #156729 (remove doc useflag as it's mostly internal drivers documentation that is available on the site and rarely useful to users, in case it can be re-added as app-doc/alsa-driver-docs), and bug #156757 (add check for CONFIG_FW_LOADER when using emu10k1 driver as it's now needed, thanks to Stefan Wimmer for reporting). Fix quoting, cleanup decisions for kernel checks, remove very ancient einfo message, use elog instead of einfo.
Package-Manager: portage-2.1.2_rc2-r5