10l: refill2() is not unused, it is used conditionally.

Fix the preprocessor directives to enable refill2() only when the
conditions under which it is used apply.

Originally committed as revision 10715 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/cabac.h

@@ -272,7 +272,7 @@ static void refill(CABACContext *c){
     c->bytestream+= CABAC_BITS/8;
 }
 
-#if 0
+#if ! ( defined(ARCH_X86) && defined(HAVE_7REGS) && defined(HAVE_EBX_AVAILABLE) && !defined(BROKEN_RELOCATIONS) )
 static void refill2(CABACContext *c){
     int i, x;