net: ipg.c fix bracing on endian swapping

rxfd->frag_info is a __le64, IPG_RFI_FRAGLEN is a cpu-endian
constant and wants to be outside of the le64_to_cpu. Fixed
in multiple places.

Also an occurrence where le64_to_cpu was used instead of cpu_to_le64

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>