scsi: sd: Cleaned up comment references to @sdp argument explanation.

In sd.c there are two comment references to 'struct scsi_device *sdp' as
an argument.  One of the references has a typo and the other should be a
reference to 'struct device *dev' instead.

Fixed by correcting the typo in the first and changing the explanation
in the second.
Signed-off-by: John Pittman <jpittman@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/sd.c

@@ -703,7 +703,7 @@ static void sd_config_discard(struct scsi_disk *sdkp, unsigned int mode)
 
 /**
  * sd_setup_discard_cmnd - unmap blocks on thinly provisioned device
- * @sdp: scsi device to operate one
+ * @sdp: scsi device to operate on
  * @rq: Request to prepare
  *
  * Will issue either UNMAP or WRITE SAME(16) depending on preference
@@ -3192,7 +3192,7 @@ static int sd_probe(struct device *dev)
  *	sd_remove - called whenever a scsi disk (previously recognized by
  *	sd_probe) is detached from the system. It is called (potentially
  *	multiple times) during sd module unload.
- *	@sdp: pointer to mid level scsi device object
+ *	@dev: pointer to device object
  *
  *	Note: this function is invoked from the scsi mid-level.
  *	This function potentially frees up a device name (e.g. /dev/sdc)