i915(FreeBSD): Restore "auto-enable" behavior of the GuC

[Why]
This now possible after the following fix in FreeBSD src's linuxkpi:

    linuxkpi: Don't destroy the mutex in `xa_destroy()`

Author: dumbbell

drivers/gpu/drm/i915/i915_params.h

@@ -49,13 +49,6 @@ struct drm_printer;
  * mode: debugfs file permissions, one of {0400, 0600, 0}, use 0 to not create
  *       debugfs file
  */
-#ifdef __FreeBSD__
-/* Changes in default values in I915_PARAMS_FOR_EACH below:
- *
- *   enable_guc: -1 -> 0
- *   GuC initialization freeze the computer.
- */
-#endif
 #define I915_PARAMS_FOR_EACH(param) \
 	param(char *, vbt_firmware, NULL, 0400) \
 	param(int, modeset, -1, 0400) \
@@ -72,7 +65,7 @@ struct drm_printer;
 	param(int, disable_power_well, -1, 0400) \
 	param(int, enable_ips, 1, 0600) \
 	param(int, invert_brightness, 0, 0600) \
-	param(int, enable_guc, 0, 0400) \
+	param(int, enable_guc, -1, 0400) \
 	param(int, guc_log_level, -1, 0400) \
 	param(char *, guc_firmware_path, NULL, 0400) \
 	param(char *, huc_firmware_path, NULL, 0400) \