scsi: libsas: Check SMP PHY control function result

Currently the SMP PHY control execution result is checked, however the
function result for the command is not.

As such, we may be missing all potential errors, like SMP FUNCTION FAILED,
INVALID REQUEST FRAME LENGTH, etc., meaning the PHY control request has
failed.

In some scenarios we need to ensure the function result is accepted, so add
a check for this.

Tested-by: Jian Luo <luojian5@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>