mpt2sas: correct scsi_{target,device} hostdata allocation

In _scsih_{slave,target}_alloc, an incorrect structure type is passed
to sizeof() when allocating storage for hostdata.  Luckily larger
structure types were used, so at least the wrong sizes were safe:

  struct scsi_device (1784 bytes) > struct MPT2SAS_DEVICE (24 bytes)
  struct scsi_target (760 bytes)  > struct MPT2SAS_TARGET (40 bytes)

This fixes the following smatch warnings:

  drivers/scsi/mpt2sas/mpt2sas_scsih.c:1295 _scsih_target_alloc()
    warn: struct type mismatch 'MPT2SAS_TARGET vs scsi_target'

  drivers/scsi/mpt2sas/mpt2sas_scsih.c:1409 _scsih_slave_alloc()
    warn: struct type mismatch 'MPT2SAS_DEVICE vs scsi_device'

Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Sreekanth Reddy <Sreekanth.Reddy@avagotech.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/mpt2sas/mpt2sas_scsih.c

@@ -1292,7 +1292,8 @@ _scsih_target_alloc(struct scsi_target *starget)
 	unsigned long flags;
 	struct sas_rphy *rphy;
 
-	sas_target_priv_data = kzalloc(sizeof(struct scsi_target), GFP_KERNEL);
+	sas_target_priv_data = kzalloc(sizeof(*sas_target_priv_data),
+				       GFP_KERNEL);
 	if (!sas_target_priv_data)
 		return -ENOMEM;
 
@@ -1406,7 +1407,8 @@ _scsih_slave_alloc(struct scsi_device *sdev)
 	struct _sas_device *sas_device;
 	unsigned long flags;
 
-	sas_device_priv_data = kzalloc(sizeof(struct scsi_device), GFP_KERNEL);
+	sas_device_priv_data = kzalloc(sizeof(*sas_device_priv_data),
+				       GFP_KERNEL);
 	if (!sas_device_priv_data)
 		return -ENOMEM;