Similar to get_workspace, majority of the callbacks is trivial, we don't
gain anything by the indirection, so replace them by a switch function.
Trivial callback implementations use the helper.
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>