drm/i915: Remove unused i915_gem_context_lookup_engine

There are no known plans to start using it either.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190709093105.24699-1-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/gem/i915_gem_context.h

@@ -197,12 +197,6 @@ i915_gem_context_unlock_engines(struct i915_gem_context *ctx)
 	mutex_unlock(&ctx->engines_mutex);
 }
 
-static inline struct intel_context *
-i915_gem_context_lookup_engine(struct i915_gem_context *ctx, unsigned int idx)
-{
-	return i915_gem_context_engines(ctx)->engines[idx];
-}
-
 static inline struct intel_context *
 i915_gem_context_get_engine(struct i915_gem_context *ctx, unsigned int idx)
 {