Fix build on iOS

Icccd542b8122c7bfa0e83 and Ia6e9f06dbb850 clashed.

Change-Id: Iaea844c9955eb29104ee32660499a67cb7224cbf
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
iOS: Fix Build error in QSGTexture

We don't do build tests for qtdeclarative, and so this guy slipped
through the cracks.

Change-Id: I2ac29c6b7ec70f4dc4ca4bc682203bbca06f0e2a
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>