spi: dw-spi: Single Register read to clear IRQs
spi: dw-spi: Single Register read to clear IRQs

Instead of clearing the RxU, RxO, and TxO IRQs individually with
3 register reads, a single read of the ICR register will do the
same thing.

Signed-off-by: Thor Thayer <e9e18c12cd15ca63116099b02663c9e3d043a667@opensource.altera.com>
Signed-off-by: Andy Shevchenko <74f0c009df510614346aa771cd21959b78cdb413@intel.com>
Signed-off-by: Mark Brown <b51b9a92386687a9ac927cebfa0f978adeb8cea5@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs