MGS-6197 [#imx-2532] GPU crash when changing gpu_govern mode

MGS-6197 [#imx-2532] GPU crash when changing gpu_govern mode

No need to power on during suspend.
1. If the GPU core is already on, then no change performed.
2. If the GPU core is already in idle/suspend/power_off it means the
   Stall has already been done.
   No need to power it on again and put into idle state again.
3. If the GPU core is in idle and we want to put into suspend or
   power_off, that will be handled inside the
   gckHARDWARE_SetPowerState().

Signed-off-by: Nicușor Cîțu <nicusor.citu@nxp.com>