eglibc: Do not specify ports multiple time to --enable-addons

eglibc: Do not specify ports multiple time to --enable-addons

* While building for mips64 I noticed a problem where eglibc
  configure did not get the mips sub arch correct during configure
  the reason was we had ports twice in configure commandline which
  ran a ports configure twice and appended machines multiple times
  to paths which then were wrong and it failed to select correct
  ABI to compile eglibc

Signed-off-by: Khem Raj <raj.khem@gmail.com>