block: Globalize bio_set and bio_vec_slab

Move struct bio_set and biovec_slab definitions to bio.h so they can
be used outside of bio.c.

Signed-off-by: Martin K. Petersen <[email protected]>
Reviewed-by: Jeff Moyer <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
2 files changed