ALSA: gus: Fix repeated probe for ISA interwave card

The legacy ISA probe tries to probe the card repeatedly, and this
would conflict with the refactoring using devres.  Put the card
creation out of the loop and only probe GUS object repeatedly.

Fixes: 5b88da3c

 ("ALSA: gus: Allocate resources with device-managed APIs")
Link: https://lore.kernel.org/r/20210907093930.29009-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>