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Add GET_CALLBACK_DATA function again as now Linux driver
supports both mailbox as well as ISR method.
Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
Signed-off-by: Jolly Shah <jolly.shah@xilinx.com>
Change-Id: Ieb99d61976e1cb718fcd1021d9cf4958e7556c81