usb: dwc2: Get host DMA device properties

The driver will automatically enable host DMA and use it if available.
This is consistent with the behavior of all existing platforms.

Read in the "snps,host-dma-disable" device property to disable it.

Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>