PCI: Constify hotplug attribute_group structures

attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by <linux/sysfs.h> work with const
attribute_group. So mark the non-const structs as const.

File size before:
text data bss dec hex filename
418 160 8 586 24a drivers/pci/hotplug/rpadlpar_sysfs.o

File size After adding 'const':
text data bss dec hex filename
482 96 8 586 232 drivers/pci/hotplug/rpadlpar_sysfs.o

Signed-off-by: Arvind Yadav <[e-mail]>
Signed-off-by: Bjorn Helgaas <[e-mail]>
Reviewed-by: Tyrel Datwyler <[e-mail]>

drivers/pci/hotplug/rpadlpar_sysfs.c

···
 	NULL,
 };
 
-static struct attribute_group dlpar_attr_group = {
+static const struct attribute_group dlpar_attr_group = {
 	.attrs = default_attrs,
 };