Add a field 'num_tags' to the esp structure to allow drivers
to overwrite the number of avialable tags if required.
Default is ESP_DEFAULT_TAGS.
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>