PVR: Upgrade to 1.9@2291151.

* Add new imgtec GPU drivers.

Thanks to dhacker29 https://github.com/dhacker29/proprietary_vendor_imgtec/commit/3515f2a1d4de5ef822cce8dbdced3079913dc3bb

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>