ppc: xilinx_ppc440_generic: Remove weak attributes

ppc: xilinx_ppc440_generic: Remove weak attributes

Now that the specific boards have been removed there is no need to
maintain the weak functions.

Fix also CamelCase to make checkpatch happy

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Acked-by: Stefan Roese <sr@denx.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Michal Simek <michal.simek@xilinx.com>