ALSA: usx2y: Fix potential memory leaks

Theoretically the initialization functions in usx2y drivers may be
called multiple times as the driver gets initialized via hwpdep
ioctl.  Meanwhile, those functions including memory allocations don't
check whether they are called twice, and they forget the old
resources, which would lead to memory leaks.

This patch adds the sanity checks about the doubly initializations to
give kernel WARNING, and returns an error in such a case.  Also, each
allocation assures to release the resources at its error path
properly.

Link: https://lore.kernel.org/r/20210517131545.27252-7-tiwai@suse.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>