nfc: virtual_ncidev: change default device permissions

Device permissions is S_IALLUGO, with many unnecessary bits. Remove them
and also remove read and write permissions from group and others.

Before the change:
crwsrwsrwt    1 0        0          10, 125 Nov 25 13:59 /dev/virtual_nci

After the change:
crw-------    1 0        0          10, 125 Nov 25 14:05 /dev/virtual_nci
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Bongsu Jeon <bongsu.jeon@samsung.com>
Link: https://lore.kernel.org/r/20211125141457.716921-1-cascardo@canonical.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/nfc/virtual_ncidev.c

@@ -202,7 +202,7 @@ static int __init virtual_ncidev_init(void)
 	miscdev.minor = MISC_DYNAMIC_MINOR;
 	miscdev.name = "virtual_nci";
 	miscdev.fops = &virtual_ncidev_fops;
-	miscdev.mode = S_IALLUGO;
+	miscdev.mode = 0600;
 
 	return misc_register(&miscdev);
 }