padata: Replace padata_attr_type default_attrs field with groups

The kobj_type default_attrs field is being replaced by the
default_groups field. Replace padata_attr_type's default_attrs field
with default_groups and use the ATTRIBUTE_GROUPS macro to create
padata_default_groups.

This patch was tested by loading the pcrypt module and verifying that
the sysfs files for the attributes in the default groups were created.

Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>