block: rename __bio_add_pc_page to bio_add_hw_page

block: rename __bio_add_pc_page to bio_add_hw_page

Rename __bio_add_pc_page() to bio_add_hw_page() and explicitly pass in a
max_sectors argument.

This max_sectors argument can be used to specify constraints from the
hardware.

Signed-off-by: Christoph Hellwig <[email protected]>
[ jth: rebased and made public for blk-map.c ]
Signed-off-by: Johannes Thumshirn <[email protected]>
Reviewed-by: Daniel Wagner <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>