video: driver: fix incorrect initialization of dmabuf

Reinitialize dmabuf pointer to NULL only after
dma_buf_put has been called on that buffer.

Change-Id: I05e8c1d0901438bc39a9bf9faeed11e228cd7675
Signed-off-by: Darshana Patil <[email protected]>

driver/vidc/src/msm_vidc_driver.c

@@ -2020,7 +2020,7 @@ int msm_vidc_process_readonly_buffers(struct msm_vidc_inst *inst,
 				ro_buf->attach, ro_buf->sg_table);
 			call_mem_op(core, dma_buf_detach, core,
 				ro_buf->dmabuf, ro_buf->attach);
-			ro_buf->dmabuf = NULL;
+			ro_buf->sg_table = NULL;
 			ro_buf->attach = NULL;
 		}
 		if (ro_buf->dbuf_get) {