sysfs/cpu: Make crash_hotplug attribute world-readable

There is no reason to restrict access to this attribute, as it merely
reports whether crash elfcorehdr is automatically updated on CPU hot
plug/unplug and/or online/offline events.

Note that since commit 7936502 ("crash: add a new kexec flag for
hotplug support"), this maps to the same flag which is world-accessible
through /sys/devices/system/memory/crash_hotplug.

Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Link: https://lore.kernel.org/r/20240711103409.319673-1-petr.tesarik@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: ptesarik

drivers/base/cpu.c

@@ -308,7 +308,7 @@ static ssize_t crash_hotplug_show(struct device *dev,
 {
 	return sysfs_emit(buf, "%d\n", crash_check_hotplug_support());
 }
-static DEVICE_ATTR_ADMIN_RO(crash_hotplug);
+static DEVICE_ATTR_RO(crash_hotplug);
 #endif
 
 static void cpu_device_release(struct device *dev)