ALSA: gus: Fix repeated probes of snd_gus_create()

GUS card object may be repeatedly probed for the legacy ISA devices,
and the behavior doesn't fit with the devres resource management.

Revert partially back to the classical way for the snd_gus_card
object, so that the repeated calls of snd_gus_create() are allowed.

Fixes: 5b88da3c

 ("ALSA: gus: Allocate resources with device-managed APIs")
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/r/20210907093930.29009-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>