v4l2allocator: Don't dup imported DMABuf FD

There is no specific needs to duplicate the FD. Unlike the exportation,
we don't depend on code that will call close. This will make debugging
easyer since the traced FD will match the exporter.

sys/v4l2/gstv4l2allocator.c

@@ -936,9 +936,6 @@ gst_v4l2_allocator_clear_dmabufin (GstV4l2Allocator * allocator,
     GST_LOG_OBJECT (allocator, "[%i] clearing DMABUF import, fd %i plane %d",
         group->buffer.index, mem->dmafd, i);
 
-    if (mem->dmafd >= 0)
-      close (mem->dmafd);
-
     /* Update memory */
     mem->mem.maxsize = 0;
     mem->mem.offset = 0;
@@ -1078,8 +1075,7 @@ gst_v4l2_allocator_import_dmabuf (GstV4l2Allocator * allocator,
 
     size = gst_memory_get_sizes (dma_mem[i], &offset, &maxsize);
 
-    if ((dmafd = dup (gst_dmabuf_memory_get_fd (dma_mem[i]))) < 0)
-      goto dup_failed;
+    dmafd = gst_dmabuf_memory_get_fd (dma_mem[i]);
 
     GST_LOG_OBJECT (allocator, "[%i] imported DMABUF as fd %i plane %d",
         group->buffer.index, dmafd, i);
@@ -1124,12 +1120,6 @@ not_dmabuf:
     GST_ERROR_OBJECT (allocator, "Memory %i is not of DMABUF", i);
     return FALSE;
   }
-dup_failed:
-  {
-    GST_ERROR_OBJECT (allocator, "Failed to dup DMABUF descriptor: %s",
-        g_strerror (errno));
-    return FALSE;
-  }
 }
 
 gboolean