drm/i915: Remove use_mmio_flip modparm, v2.

This has been unused since commit afa8ce5b
("drm/i915: Nuke legacy flip queueing code").

Changes since v1:
- Rebase on top of all the changes to modparams.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
\o/-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171004094416.31306-1-maarten.lankhorst@linux.intel.com

drivers/gpu/drm/i915/i915_params.c

@@ -146,9 +146,6 @@ i915_param_named(disable_display, bool, 0400,
 i915_param_named_unsafe(enable_cmd_parser, bool, 0400,
 	"Enable command parsing (true=enabled [default], false=disabled)");
 
-i915_param_named_unsafe(use_mmio_flip, int, 0600,
-	"use MMIO flips (-1=never, 0=driver discretion [default], 1=always)");
-
 i915_param_named(mmio_debug, int, 0600,
 	"Enable the MMIO debug code for the first N failures (default: off). "
 	"This may negatively affect performance.");

drivers/gpu/drm/i915/i915_params.h

@@ -49,7 +49,6 @@
 	param(int, guc_log_level, -1) \
 	param(char *, guc_firmware_path, NULL) \
 	param(char *, huc_firmware_path, NULL) \
-	param(int, use_mmio_flip, 0) \
 	param(int, mmio_debug, 0) \
 	param(int, edp_vswing, 0) \
 	param(int, reset, 2) \

drivers/gpu/drm/i915/intel_lrc.c

@@ -244,8 +244,7 @@ int intel_sanitize_enable_execlists(struct drm_i915_private *dev_priv, int enabl
 		return 0;
 
 	if (HAS_LOGICAL_RING_CONTEXTS(dev_priv) &&
-	    USES_PPGTT(dev_priv) &&
-	    i915_modparams.use_mmio_flip >= 0)
+	    USES_PPGTT(dev_priv))
 		return 1;
 
 	return 0;