dw_dmac: add support for Lynxpoint DMA controllers

Intel Lynxpoint PCH Low Power Subsystem has DMA controller to support general
purpose serial buses like SPI, I2C, and HSUART. This controller is enumerated
from ACPI namespace with ACPI ID INTL9C60.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>