ALSA: usb-audio: Fix a DMA to stack memory bug

ALSA: usb-audio: Fix a DMA to stack memory bug

The usb_get_descriptor() function does DMA so we're not allowed
to use a stack buffer for that.  Doing DMA to the stack is not portable
all architectures.  Move the "new_device_descriptor" from being stored
on the stack and allocate it with kmalloc() instead.

Fixes: b909df18ce2a ("ALSA: usb-audio: Fix potential out-of-bound accesses for Extigy and Mbox devices")
Cc: stable@kernel.org
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://patch.msgid.link/60e3aa09-039d-46d2-934c-6f123026c2eb@stanley.mountain
Signed-off-by: Takashi Iwai <tiwai@suse.de>