Platform/SbsaQemu: add XHCI support and replace EHCI

As sbsa-ref does not have DRAM below 4G, it cannot utilize EHCI
that only has 32-bit DMA capablity and sbsa-ref board uses xhci
to replace ehci.

This updates DSDT to match the platform xhci controller with two
usb ports changed from type A to type C.

Signed-off-by: Yuquan Wang <wangyuquan1236@phytium.com.cn>
Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>