[PATCH] scsi_mid_low_api.txt update

From: Douglas Gilbert <dougg@torque.net>

Attached is an update of the scsi_mid_low_api text
document. The first attachment is a gzipped patch against
lk 2.6.0-test4 and the second one is the file gzipped.

Changes:
   - add "Calling context:" entry to interface functions
   - add "Might block:" entry to mid level functions
   - drop scsi_set_device_offline() + command()
   - change references to reflect transfer of headers to
     include/scsi/scsi_*.h
   - try to define what a "scsi host" is
   - typos + grammar

Thanks to Randy Dunlap, Alan Stern amd Christoph Hellwig
for their input. Comments welcome.