[SCSI] Remove ->pid field from scsi_cmnd

The pid field is a duplicate of the serial_number field and has been
scheduled for removal for a long time.  A few drivers were still using
it, so just change them to use serial_number instead.

Signed-off-by: Matthew Wilcox <[email protected]>
Signed-off-by: James Bottomley <[email protected]>
13 files changed