ALSA: ens137x: Allocate resources with device-managed APIs

This patch converts the resource management in PCI esn137x drivers
with devres as a clean up.  Each manual resource management is
converted with the corresponding devres helper, the devres helper is
used for the DMA buffer page allocations, and the card object release
is managed now via card->private_free instead of a lowlevel
snd_device.

This should give no user-visible functional changes.

Link: https://lore.kernel.org/r/20210715075941.23332-17-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>