[PATCH] libata: cosmetic changes to sense generation functions

* s/ata_gen_ata_desc_sense/ata_gen_passthru_sense/

* s/ata_gen_fixed_sense/ata_gen_ata_sense/

* make both functions static

* neither function has locking requirement, change it to None.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>