Support for SFP port remapping.

SFPI drivers may now provide a port index remapping function that translates
the user-specified SFP port number before calling an SFPI interfaces.

This is to support platforms for which the SFP logical port number may be
different from the underlying implementation due to platform variations
or implementation details.
Merge branch 'master' of github.com:opennetworklinux/ONLP