Deleted repeated code block

The block of code skipped testing the current mode if the
reference frame is AltRef, the mv is not (0,0) and
ARNR filtering is disabled.

This block of code has already been tested above if the
macro CONFIG_SEGFEATURES is set to 0.

Change-Id: I3f5710bb8270caad06c9a0eee59fa0daf1f70776