iris: Mark render batches as non-recoverable.

iris: Mark render batches as non-recoverable.

Adapted from Chris Wilson's patch.  The comment is largely his.

Currently, when iris hangs the GPU, it will continue sending batches
which incrementally update the state, assuming it's preserved across
batches.  However, the kernel's GPU reset support reinitializes the
guilty context to the default GPU state (reasonably not wanting to
trust the current state).  This ends up resetting critical things
like STATE_BASE_ADDRESS, causing memory accesses in all subsequent
batches to be garbage, and almost certainly result in more hangs
until we're banned or we kill the machine.

We now ask the kernel to ban our render context immediately, so we
notice we've gone off the rails as fast as possible.  Eventually, we'll
attempt to recover and continue.  For now, we just avoid torching the
GPU over and over.