tests/i915_module_load: Use new name of fault injection module parameter

Name of the i915 module parameter providing fault injection function is
changing for consistency with a new convention of naming i915 driver
internal functions called from the driver PCI .probe entry point.  Adjust
the test to use the new name.

[ickle: keep the old parameter name around for stable testing]

Suggested-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Cc: Michał Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Piotr Piórkowski <piotr.piorkowski@intel.com>
Cc: Tomasz Lis <tomasz.lis@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>