[Intel-gfx] Updated GPU reset at init patch

[Jesse Barnes]

I wasn't able to reproduce the performance hit after reset you guys were
seeing, but did see that the way I was doing reset may have been causing
more general trouble (I got GPU hangs at init) which could explain what
you were seeing.

So please give this patch a try and see if it still allows you to get
RC6 without any perf penalty.

Thanks,
Jesse