drm/i915: Mark i915.reset as unsigned

We have been using '-1' to mean the maximum i915.reset level in the
belief that it was unsigned... This turns out to have been a grave
error, and instead of setting the default reset mechanism in igt,
we have been disabling reset!

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200205123757.1834947-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_params.h

@@ -63,7 +63,7 @@ struct drm_printer;
 	param(char *, dmc_firmware_path, NULL, 0400) \
 	param(int, mmio_debug, -IS_ENABLED(CONFIG_DRM_I915_DEBUG_MMIO), 0600) \
 	param(int, edp_vswing, 0, 0400) \
-	param(int, reset, 3, 0600) \
+	param(unsigned int, reset, 3, 0600) \
 	param(unsigned int, inject_probe_failure, 0, 0600) \
 	param(int, fastboot, -1, 0600) \
 	param(int, enable_dpcd_backlight, -1, 0600) \