sbp2: remove manipulation of inquiry response

This code became ineffective a few Linux releases ago and is not
required anyway.

Note from Christoph Hellwig: scsi_cmnd.request_buffer is always a
scatterlist these days.  Checking random bites into it and then
mangling the data in sbp2_check_sbp2_response will cause really bad
memory corruption when you're not lucky enough to have the check not
trigger by luck.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Ben Collins <bcollins@ubuntu.com>