Revert "drm/i915: Try enabling RC6 by default (again)"

This reverts commit 4e20fa65.

Francesco Allertsen still has a broken configuration.
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/i915/i915_drv.c

@@ -62,7 +62,7 @@ module_param_named(semaphores, i915_semaphores, int, 0600);
 MODULE_PARM_DESC(semaphores,
 		"Use semaphores for inter-ring sync (default: false)");
 
-unsigned int i915_enable_rc6 __read_mostly = 1;
+unsigned int i915_enable_rc6 __read_mostly = 0;
 module_param_named(i915_enable_rc6, i915_enable_rc6, int, 0600);
 MODULE_PARM_DESC(i915_enable_rc6,
 		"Enable power-saving render C-state 6 (default: true)");