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: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>