In patch 1cfe474b ("Simplify motion var parameters in reconinter.h"),
I moved some code from the header down into
reconinter.c. Unfortunately, I managed to drop it inside an #ifdef
CONFIG_EXT_INTER/#endif pair, which means the build won't work if
compiled with --disable-ext_inter.

This patch moves the hunk of code to above the #ifdef.

BUG=aomedia:694

Change-Id: I1e83bb500bcb607ee5911027b7c4787184703a57