gpu: host1x: returning success instead of -ENOMEM

There is a mistake here so it returns PTR_ERR(NULL) which is success
instead of -ENOMEM.

Signed-off-by: Dan Carpenter <[e-mail]>
Signed-off-by: Thierry Reding <[e-mail]>

drivers/gpu/host1x/job.c

···
 							 &job->gather_copy,
 							 GFP_KERNEL);
 	if (!job->gather_copy_mapped) {
-		int err = PTR_ERR(job->gather_copy_mapped);
 		job->gather_copy_mapped = NULL;
-		return err;
+		return -ENOMEM;
 	}
 
 	job->gather_copy_size = size;