[ALSA] clean up card features

EMU10K1/EMU10K2 driver
This patch converts the emu10k1 driver to use the card capabilities
structure for some more things.

Not extensively tested but seems to work.

Signed-off-by: Lee Revell <rlrevell@joe-job.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>