drm/i915/gvt: Do not use I915_NUM_ENGINES to iterate over the mocs regs array

The mocs reg array is defined locally but then we iterate over its
elements using I915_NUM_ENGINES. There is no 'hard' connection between
I915_NUM_ENGINES and the regs array and there will be problems if either
of them increases.

Use the size of the mocs reg array instead to safely iterate over it.
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Cc: Weinan Li <weinan.z.li@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/i915/gvt/mmio_context.c

@@ -167,7 +167,7 @@ static void load_render_mocs(struct drm_i915_private *dev_priv)
 	};
 	int ring_id, i;
 
-	for (ring_id = 0; ring_id < I915_NUM_ENGINES; ring_id++) {
+	for (ring_id = 0; ring_id < ARRAY_SIZE(regs); ring_id++) {
 		offset.reg = regs[ring_id];
 		for (i = 0; i < 64; i++) {
 			gen9_render_mocs.control_table[ring_id][i] =