powerpc/85xx: Remove unused pci fixup hooks on c293pcie

The c293pcie board is an endpoint device and it doesn't need PM,
so remove hooks pcibios_fixup_phb and pcibios_fixup_bus.

Signed-off-by: Hou Zhiqiang <B48286@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>