drm/i915/gen10: Set value of Indirect Context Offset for gen10

drm/i915/gen10: Set value of Indirect Context Offset for gen10

Indirect Context Offset Pointer has changed for Cannonlake.

INDIRECT_CTX_OFFSET[15:6] valid value for CNL is 19h per Spec.

v2: rebased to intel_lr_indirect_ctx_offset

v3: Commit message added per Tvrtko request.

Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1496781040-20888-9-git-send-email-rodrigo.vivi@intel.com