[ALSA] pci: select FW_LOADER instead of depending on it

Let the AudioScience, Echoaudio and Riptide drivers select FW_LOADER
instead of depending on it so that they can be configured without having
to enable FW_LOADER manually.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>