drm/i915/gt: Use the BIT when checking the flags, not the index

In converting over to using set_bit()/test_bit(), when manually
inspecting the rq->fence.flags, we need to use BIT().

Fixes: e1c31fb5 ("drm/i915: Merge i915_request.flags with i915_request.fence.flags")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200115122509.2673075-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_lrc.c

@@ -1535,7 +1535,8 @@ static bool can_merge_rq(const struct i915_request *prev,
 		return true;
 
 	if (unlikely((prev->fence.flags ^ next->fence.flags) &
-		     (I915_FENCE_FLAG_NOPREEMPT | I915_FENCE_FLAG_SENTINEL)))
+		     (BIT(I915_FENCE_FLAG_NOPREEMPT) |
+		      BIT(I915_FENCE_FLAG_SENTINEL))))
 		return false;
 
 	if (!can_merge_ctx(prev->context, next->context))