Small optimization while removing warning

Small optimization while removing warning

Removed the helper array and its initialization loop as we can achieve the
same with two variables in one loop.

This patch also removes the warning below:

> gen8_mfc.c:2735:9: warning: variable 'i' is incremented both in the loop
> header and in the loop body [-Wfor-loop-analysis]
>         i++;
>         ^
> gen8_mfc.c:2732:25: note: incremented here
>     for (i = 0; i < 64; i++) {
>                         ^

Signed-off-by: Victor Toso <victortoso@redhat.com>