usb: host: xhci-plat: Make enum xhci_plat_type start at a non zero value
Otherwise generic-xhci and xhci-platform which have no data get wrongly
detected as XHCI_PLAT_TYPE_MARVELL_ARMADA by xhci_plat_type_is().
This fixes a regression in v4.5 for STiH407 family SoC's which use the
synopsis dwc3 IP, whereby the disable_clk error path gets taken due to
wrongly being detected as XHCI_PLAT_TYPE_MARVELL_ARMADA and the hcd never
gets added.
I suspect this will also fix other dwc3 DT platforms such as Exynos,
although I've only tested on STih410 SoC.