mtip32xx: fix up the checking for internal command failure

This fixes up two commits that have touched this driver. The
command status field is now a blk_status_t, so we can't check
for < 0 and we definitely can't assume it's holding -Exxxx error
values. All we care about here is whether ->status is zero or not.
Check for that, and remove the various attempts at smart error
reporting. Just log to dmesg what command failed, and the
blk_status_t value.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 2a842aca ("block: introduce new block status code type")
Fixes: 3f5e6a35

 ("mtip32xx: convert internal command issue to block IO path")
Signed-off-by: Jens Axboe <axboe@kernel.dk>