[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 <willy@linux.intel.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/qla1280.c b/drivers/scsi/qla1280.c
index 54d8bdf..fba8aa8 100644
--- a/drivers/scsi/qla1280.c
+++ b/drivers/scsi/qla1280.c
@@ -4086,7 +4086,7 @@
 	   } */
 	printk("  tag=%d, transfersize=0x%x \n",
 	       cmd->tag, cmd->transfersize);
-	printk("  Pid=%li, SP=0x%p\n", cmd->pid, CMD_SP(cmd));
+	printk("  Pid=%li, SP=0x%p\n", cmd->serial_number, CMD_SP(cmd));
 	printk(" underflow size = 0x%x, direction=0x%x\n",
 	       cmd->underflow, cmd->sc_data_direction);
 }