i965/gen10: Implement WaForceRCPFEHangWorkaround

i965/gen10: Implement WaForceRCPFEHangWorkaround

This workaround doesn't fix any of the piglit hangs we've seen
on CNL. But it might be fixing something we haven't tested yet.

V2: Add the check for Post Sync Operation.
    Update the workaround comment.
    Use braces around if-else.

Signed-off-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Rafael Antognolli <rafael.antognolli@intel.com>
Reviewed-by: Nanley Chery <nanley.g.chery@intel.com>