usb: renesas_usbhs: add usbhsf_dma_init_pdev() function

To add support for requesting DT DMA in the future, this patch adds
usbhsf_dma_init_pdev() function.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>