gpu: pvr: Disable driver if SGX HW recovery fails

gpu: pvr: Disable driver if SGX HW recovery fails

At the moment SGX HW recovery doesn't succeed always and keeps the
processes using the driver blocked. To avoid this give up after a
number of retries and disable further IOCTLs or interaction with
the HW. This would still allow a complete restart of the graphics
stack including reloading the drivers and restarting the relevant
processes.

The final fix is of course to find out why the recovery doesn't
succeed.

Signed-off-by: Imre Deak <imre.deak@nokia.com>