Pass correct parameter to CTR5() in bus_dmamap_load_uio.

Sponsored by:	Intel
Do not add 1 to nsegs before passing to CTR5(), since nsegs
has already been incremented before these calls.

Sponsored by:	Intel
Add CTR5() to bus_dmamap_load_ccb, similar to other bus_dmamap_load_*
functions.

Sponsored by:	Intel
Add bus_dmamap_load_bio for non-CAM disk drivers that wish to enable
unmapped I/O.

Sponsored by:	Intel
Reviewed by:	kib