ALSA: ens137x: More constification

Apply const prefix to the quirk entry, forgotten in the previous fix.

Just for minor optimization and no functional changes.

Link: https://lore.kernel.org/r/20200105144823.29547-64-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/ens1370.c

@@ -1574,7 +1574,7 @@ static int es1371_quirk_lookup(struct ensoniq *ensoniq,
 	return 0;
 }
 
-static struct es1371_quirk es1371_spdif_present[] = {
+static const struct es1371_quirk es1371_spdif_present[] = {
 	{ .vid = PCI_VENDOR_ID_ENSONIQ, .did = PCI_DEVICE_ID_ENSONIQ_CT5880, .rev = CT5880REV_CT5880_C },
 	{ .vid = PCI_VENDOR_ID_ENSONIQ, .did = PCI_DEVICE_ID_ENSONIQ_CT5880, .rev = CT5880REV_CT5880_D },
 	{ .vid = PCI_VENDOR_ID_ENSONIQ, .did = PCI_DEVICE_ID_ENSONIQ_CT5880, .rev = CT5880REV_CT5880_E },