drm/xe: Emit a render cache flush after each rcs/ccs batch

We need to flush render caches before fence signalling, where we might
release the memory for reuse. We can't rely on userspace doing this,
so flush render caches after the batch, but before user fence- and
dma_fence signalling.

Copy the cache flush from i915, but omit PIPE_CONTROL_FLUSH_L3, since it
should be implied by the other flushes. Also omit
PIPE_CONTROL_TLB_INVALIDATE since there should be no apparent need to
invalidate TLB after batch completion.

v2:
- Update Makefile for OOB WA.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Tested-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com> #1
Reported-by: José Roberto de Souza <jose.souza@intel.com>
Link: #291
Closes: #291