pcmcia_get_{first,next}_region are tricky: they're used
only by ds.c, but to keep backwards compatibility proper
wrappers are needed (for the moment). However, match_region()
doesn't work without knowing about ds.c's handle, it seems...
but wait:

    while (list != NULL) {
        if (!(handle->Attributes & INFO_MTD_CLIENT) ||
            (strcmp(handle->dev_info, list->dev_info) == 0)) {
            *match = list->info;
            return CS_SUCCESS;
        }
        list = list->info.next;
    }

as ds.c's handle doesn't have INFO_MTD_CLIENT, the if always
succeeds -- allowing is to simplify it for ds.c. However, this
means we need special functions for ds.c. It's not too large,
fortunately.