remove unnecessary CONFIG addition
remove unnecessary CONFIG addition

qt is already added by spec_pre.prf.

Change-Id: I72dc555583e5a3453050eab876f34cece8e00b47
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@digia.com>

kobolabs/qtgraphicaleffects