scsi: libsas: Stop hardcoding SAS address length

Many times we use 8 for SAS address length, while we already have a macro
for this - SAS_ADDR_SIZE.

Replace instances of this with the macro. However, don't touch the SAS
address array sizes sas.h, as these are defined according to the SAS spec.

Some missing whitespaces are also added, and whitespace indentation
in sas_hash_addr() is also fixed (see sas_hash_addr()).

Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>