[POWERPC] Fix PCI indirect for big-endian cfg_addr

We didn't actually propogate the flag we pass into setup_indirect_pci()
to set indirect_type and thus were getting the wrong endianness if
PPC_INDIRECT_TYPE_BIG_ENDIAN was set.

Also, we need to or in additional flags rather than just doing a
direct assignment.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>