[SCSI] aacraid: use sg buffer copy helper functions

This replaces aac_internal_transfer with scsi_sg_copy_to/from_buffer.

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