drm/i915: Skip pxp init if gt is wedged

The gt wedged could be triggered by missing guc firmware file, HW not
working, etc. Once triggered, it means all gt usage is dead, therefore we
can't enable pxp under this fatal error condition.

v2: Updated commit message.
v3: Updated return code check.

Signed-off-by: Zhanjun Dong <zhanjun.dong@intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231113224953.378534-1-zhanjun.dong@intel.com