Documentation/dts: Move FSL board-specific bindings out of /powerpc

Since the same board components can be used across ARM and PPC board families,
this patch moves the FSL board-specific bindings out of bindings/powerpci.

While at it, this patch also adds the bindings for QIXIS FPGA controller
found on FSL LS2080A boards. These boards have an on-board FPGA/CPLD
connected to the IFC controller.

Signed-off-by: Bhupesh Sharma <bhupesh.sharma@freescale.com>
Signed-off-by: Jaiprakash Singh <b44839@freescale.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>