Move XLP PCI UART device to sys/mips/nlm/dev/ directory. Other
drivers for the XLP SoC devices will be added here as well.
Update uart_cpu_xlp.c and uart_pci_xlp.c use macros for uart port,
speed and IO frequency.
- update xlp_machdep.c to read arguments from FDT if FDT support is
compiled in.
- define rmi_uart_bus_space, and use it as fdtbus_bs_tag
- update conf files for FDT support
- add default dts file xlp-basic.dts
* Update the hardware access register definitions and functions to bring
them in line with other Netlogic software.
* Update the platform bus to use PCI even for on-chip devices. Add a dummy
PCI driver to ignore on-chip devices which do not need driver.
* Provide memory and IRQ resource allocation code for on-chip devices
which cannot get it from PCI config.
* add support for on-chip PCI and USB interfaces.
* update conf files, enable pci and retain old MAXCPU until we can support
>32 cpus.
Approved by: re(kib), jmallett
