scsi: core: sysfs: Fix setting device state to SDEV_RUNNING

This fixes an issue added in commit 4edd8cd4 ("scsi: core: sysfs: Fix
hang when device state is set via sysfs") where if userspace is requesting
to set the device state to SDEV_RUNNING when the state is already
SDEV_RUNNING, we return -EINVAL instead of count. The commmit above set ret
to count for this case, when it should have set it to 0.

Link: https://lore.kernel.org/r/20211120164917.4924-1-michael.christie@oracle.com
Fixes: 4edd8cd4 ("scsi: core: sysfs: Fix hang when device state is set via sysfs")
Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi_sysfs.c

@@ -812,7 +812,7 @@ store_state_field(struct device *dev, struct device_attribute *attr,
 
 	mutex_lock(&sdev->state_mutex);
 	if (sdev->sdev_state == SDEV_RUNNING && state == SDEV_RUNNING) {
-		ret = count;
+		ret = 0;
 	} else {
 		ret = scsi_device_set_state(sdev, state);
 		if (ret == 0 && state == SDEV_RUNNING)