perf: arm-ni: Remove spurious NULL in attribute_group definition

This NULL value is most-likely a copy-paste error from an array
definition. So far the NULL didn't have any effect.
As there will be a union in struct attribute_group at this location,
it will trigger a compiler warning.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20241118-sysfs-const-attribute_group-fixes-v1-1-48e0b0ad8cba@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: t-8ch

drivers/perf/arm-ni.c

@@ -247,7 +247,6 @@ static struct attribute *arm_ni_other_attrs[] = {
 
 static const struct attribute_group arm_ni_other_attr_group = {
 	.attrs = arm_ni_other_attrs,
-	NULL
 };
 
 static const struct attribute_group *arm_ni_attr_groups[] = {