dmaengine: idma64: use lo_hi_readq() / lo_hi_writeq()

There are already helper functions to do 64-bit I/O on 32-bit machines, thus we
don't need to reinvent the wheel. In our case we can't use readq() / writeq()
even on 64-bit kernel since there is a hardware limitation (OCP bus is a 32-bit
bus).

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>