mmc: dw_mmc: Fixes data read when receiving DTO interrupt in FIFO mode

The data read is not working when using FIFO mode.

From DesignWare databook, when a Data_Transfer_Over (DTO) interrupt is
received, the software should read the remaining data from FIFO.

Add DTO interrupt checking on data read path and clear interrupts before
start reading from FIFO. So, it doesn't clear the next pending
interrupts unintentionally after read from FIFO.

Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>