drm/i915: drop unused i915.disable_vtd_wa module parameter

This is a manual revert of

commit 7a10dfa638be26669f0987b6a21a65e6b39356b2
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue Apr 1 09:33:47 2014 +0200

    drm/i915: Add debug module option for VTd validation

as no users have appeared.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1455621493-6865-2-git-send-email-jani.nikula@intel.com

drivers/gpu/drm/i915/i915_params.c

@@ -49,7 +49,6 @@ struct i915_params i915 __read_mostly = {
 	.invert_brightness = 0,
 	.disable_display = 0,
 	.enable_cmd_parser = 1,
-	.disable_vtd_wa = 0,
 	.use_mmio_flip = 0,
 	.mmio_debug = 0,
 	.verbose_state_checks = 1,
@@ -168,9 +167,6 @@ MODULE_PARM_DESC(invert_brightness,
 module_param_named(disable_display, i915.disable_display, bool, 0400);
 MODULE_PARM_DESC(disable_display, "Disable display (default: false)");
 
-module_param_named_unsafe(disable_vtd_wa, i915.disable_vtd_wa, bool, 0600);
-MODULE_PARM_DESC(disable_vtd_wa, "Disable all VT-d workarounds (default: false)");
-
 module_param_named_unsafe(enable_cmd_parser, i915.enable_cmd_parser, int, 0600);
 MODULE_PARM_DESC(enable_cmd_parser,
 		 "Enable command parsing (1=enabled [default], 0=disabled)");

drivers/gpu/drm/i915/i915_params.h

@@ -56,7 +56,6 @@ struct i915_params {
 	bool load_detect_test;
 	bool reset;
 	bool disable_display;
-	bool disable_vtd_wa;
 	bool enable_guc_submission;
 	bool verbose_state_checks;
 	bool nuclear_pageflip;