drm/i915/pmu: Drop I915_ENGINE_SAMPLE_MAX from uapi headers

We have agreed during the engine classes discussion that fields marked as
non-ABI are better left out altogether from uapi headers.

v2: Use a local define for maintanability. (Chris Wilson)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123100701.18430-1-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -358,6 +358,7 @@ struct intel_engine_cs {
 		 *
 		 * Our internal timer stores the current counters in this field.
 		 */
+#define I915_ENGINE_SAMPLE_MAX (I915_SAMPLE_SEMA + 1)
 		struct i915_pmu_sample sample[I915_ENGINE_SAMPLE_MAX];
 		/**
 		 * @busy_stats: Has enablement of engine stats tracking been

include/uapi/drm/i915_drm.h

@@ -110,8 +110,7 @@ enum drm_i915_gem_engine_class {
 enum drm_i915_pmu_engine_sample {
 	I915_SAMPLE_BUSY = 0,
 	I915_SAMPLE_WAIT = 1,
-	I915_SAMPLE_SEMA = 2,
-	I915_ENGINE_SAMPLE_MAX /* non-ABI */
+	I915_SAMPLE_SEMA = 2
 };
 
 #define I915_PMU_SAMPLE_BITS (4)