usb: renesas_usbhs: change function call orfer in usbhsf_dma_prepare_push()

Since usbhsf_dma_{un}map() will use the "fifo" data in the near future,
this patch changes function call orfer in usbhsf_dma_prepare_push().

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