ppc: xilinx-ppc440-generic: Cleanout header files

ppc: xilinx-ppc440-generic: Cleanout header files

Now that there is only one header file for all ppc440 files, merge
header files.

Signed-off-by: Ricardo Ribalda Delgado <[email protected]>
Reviewed-by: Bin Meng <[email protected]>
Reviewed-by: Tom Rini <[email protected]>
Acked-by: Stefan Roese <[email protected]>
Signed-off-by: Michal Simek <[email protected]>
Reviewed-by: Michal Simek <[email protected]>