ALSA: usb-audio: Enable .product_name override for Emagic, Unitor 8.

The Emagic Unitor 8 does not provide iManufacturer and iProduct fields
in its device descriptor. These fields are used by alsa to make build the
device name. Thus uncomment the .product-name in the quirks-table.

Without this change the device shows up as 'USB Device 0x86a:0x01'.

Output of lsusb and amidi:
https://gist.github.com/ensonic/7820a102e91f31575be355da2b6b33bc



Signed-off-by: Stefan Sauer <ensonic@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>