avr32: fix uclibc build using recent kernel headers

avr32: fix uclibc build using recent kernel headers

Using kernel headers newer than 3.6.x, uclibc 0.9.31.1 fails to build:

  In file included from output/host/usr/avr32-buildroot-linux-uclibc/sysroot/usr/include/linux/rtnetlink.h:6,
                 from libc/inet/netlinkaccess.h:34,
                 from libc/inet/if_index.c:36:
  output/host/usr/avr32-buildroot-linux-uclibc/sysroot/usr/include/linux/if_link.h:314: error: expected specifier-qualifier-list before '__be16'
  make[1]: *** [libc/inet/if_index.os] Error 1
  make[1]: Leaving directory `output/build/uclibc-0.9.31.1'
  make: *** [output/build/uclibc-0.9.31.1/.stamp_built] Error 2

This patch adjusts the system type definitions in the netlinkaccess.h
header, updating the types to match those used in uClibc 0.9.33.2.

Signed-off-by: Simon Dawson <spdawson@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>