Eliminate scsi_scsi_cmd() now that ss(4) is gone and with it the

Eliminate scsi_scsi_cmd() now that ss(4) is gone and with it the
last bastardized sync and buf call through scsi_scsi_cmd(). Flatten
code to call scsi_xs_sync() directly for all commands.

Airplane typos shaken out by various.

ok dlg@ matthew@ deraadt@