ACPI / configfs: Mark local data structures static

There is no need to have non-static local data structures. otherwise
sparse is not happy:

  CHECK   drivers/acpi/acpi_configfs.c
drivers/acpi/acpi_configfs.c:100:31: warning: symbol 'acpi_table_bin_attrs' was not declared. Should it be static?
drivers/acpi/acpi_configfs.c:196:27: warning: symbol 'acpi_table_attrs' was not declared. Should it be static?
drivers/acpi/acpi_configfs.c:236:34: warning: symbol 'acpi_table_group_ops' was not declared. Should it be static?

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>