cpu: Remove spurious NULL in attribute_group definition

This NULL value is most-likely a copy-paste error from an array
definition. The NULL doesn't have any effect.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20241118-sysfs-const-attribute_group-fixes-v1-3-48e0b0ad8cba@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: t-8ch

kernel/cpu.c

@@ -2866,7 +2866,6 @@ static struct attribute *cpuhp_cpu_attrs[] = {
 static const struct attribute_group cpuhp_cpu_attr_group = {
 	.attrs = cpuhp_cpu_attrs,
 	.name = "hotplug",
-	NULL
 };
 
 static ssize_t states_show(struct device *dev,
@@ -2898,7 +2897,6 @@ static struct attribute *cpuhp_cpu_root_attrs[] = {
 static const struct attribute_group cpuhp_cpu_root_attr_group = {
 	.attrs = cpuhp_cpu_root_attrs,
 	.name = "hotplug",
-	NULL
 };
 
 #ifdef CONFIG_HOTPLUG_SMT
@@ -3020,7 +3018,6 @@ static struct attribute *cpuhp_smt_attrs[] = {
 static const struct attribute_group cpuhp_smt_attr_group = {
 	.attrs = cpuhp_smt_attrs,
 	.name = "smt",
-	NULL
 };
 
 static int __init cpu_smt_sysfs_init(void)