[SCSI] add scsi_build_sense_buffer helper function

This adds scsi_build_sense_buffer, a simple helper function to build
sense data in a buffer.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>