staging: ion: Use PTR_ERR_OR_ZERO

PTR_RET is deprecated. Use PTR_ERR_OR_ZERO instead.
While at it also use PTR_ERR_OR_ZERO in ion.c to simplify
the code.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/ion/ion.c

@@ -16,6 +16,7 @@
  */
 
 #include <linux/device.h>
+#include <linux/err.h>
 #include <linux/file.h>
 #include <linux/freezer.h>
 #include <linux/fs.h>
@@ -1017,9 +1018,7 @@ static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start,
 	mutex_lock(&buffer->lock);
 	vaddr = ion_buffer_kmap_get(buffer);
 	mutex_unlock(&buffer->lock);
-	if (IS_ERR(vaddr))
-		return PTR_ERR(vaddr);
-	return 0;
+	return PTR_ERR_OR_ZERO(vaddr);
 }
 
 static void ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf, size_t start,

drivers/staging/android/ion/ion_heap.c

@@ -247,7 +247,7 @@ int ion_heap_init_deferred_free(struct ion_heap *heap)
 	if (IS_ERR(heap->task)) {
 		pr_err("%s: creating thread for deferred free failed\n",
 		       __func__);
-		return PTR_RET(heap->task);
+		return PTR_ERR_OR_ZERO(heap->task);
 	}
 	return 0;
 }