Revert "Revert "ALSA: usx2y: Fix potential NULL pointer dereference""

This reverts commit 4667a6fc

.

Takashi writes:
	I have already started working on the bigger cleanup of this driver
	code based on 5.13-rc1, so could you drop this revert?

I missed our previous discussion about this, my fault for applying it.

Reported-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>