Move check of IFF_LOWER_UP after all includes.

The latest uapi kernel headers use an enum for values such as
IFF_LOWER_UP. This code defines IFF_LOWER_UP and causes the inclusion
of if.h later on to mess up the enum definition.

Move the IFF_LOWER_UP check after all of the includes.

Change-Id: I9d9ce63a63bb6fc82a2424776f5aa6700cc34239