dma-buf: cleanup dma_buf_export() to make it easily extensible

[Dan Carpenter]

Hello Sumit Semwal,

The patch 817bd7253291: "dma-buf: cleanup dma_buf_export() to make it
easily extensible" from Jan 23, 2015, leads to the following static
checker warning:

	drivers/staging/android/ion/ion.c:1112 ion_share_dma_buf()
	error: potentially dereferencing uninitialized 'buffer'.

drivers/staging/android/ion/ion.c
  1103  struct dma_buf *ion_share_dma_buf(struct ion_client *client,
  1104                                                  struct ion_handle *handle)
  1105  {
  1106          struct ion_buffer *buffer;
                                   ^^^^^^
  1107          struct dma_buf *dmabuf;
  1108          bool valid_handle;
  1109          DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
  1110  
  1111          exp_info.ops = &dma_buf_ops;
  1112          exp_info.size = buffer->size;
                                ^^^^^^
  1113          exp_info.flags = O_RDWR;
  1114          exp_info.priv = buffer;
                                ^^^^^^
And here also.

  1115  

regards,
dan carpenter