drm/msm: Don't increase priv->num_aspaces until we know that it fits

priv->num_aspaces is increased and then checked to see if it still fits
in the priv->aspace array.  If it doesn't, we warn and exit but
priv->num_aspaces remains incremented.

Don't incremement the count until we know that it fits in the array.
Signed-off-by: NJordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: NRob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/msm_drv.c

@@ -55,14 +55,13 @@ int msm_register_address_space(struct drm_device *dev,
 		struct msm_gem_address_space *aspace)
 {
 	struct msm_drm_private *priv = dev->dev_private;
-	int idx = priv->num_aspaces++;
 
-	if (WARN_ON(idx >= ARRAY_SIZE(priv->aspace)))
+	if (WARN_ON(priv->num_aspaces >= ARRAY_SIZE(priv->aspace)))
 		return -EINVAL;
 
-	priv->aspace[idx] = aspace;
+	priv->aspace[priv->num_aspaces] = aspace;
 
-	return idx;
+	return priv->num_aspaces++;
 }
 
 #ifdef CONFIG_DRM_MSM_REGISTER_LOGGING