drm/i915: Make I915_GEM_IDLE_TIMEOUT into a macro

Currently we use HZ/5 for detecting a dead gpu on startup, and we will
wish to reuse this value for detecting a dead gpu on suspend, so convert
it into a macro for later convenience.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190307104530.21745-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem.c

@@ -4684,7 +4684,9 @@ static int __intel_engines_record_defaults(struct drm_i915_private *i915)
 	if (err)
 		goto err_active;
 
-	if (i915_gem_wait_for_idle(i915, I915_WAIT_LOCKED, HZ / 5)) {
+	if (i915_gem_wait_for_idle(i915,
+				   I915_WAIT_LOCKED,
+				   I915_GEM_IDLE_TIMEOUT)) {
 		i915_gem_set_wedged(i915);
 		err = -EIO; /* Caller will declare us wedged */
 		goto err_active;

drivers/gpu/drm/i915/i915_gem.h

@@ -75,6 +75,8 @@ struct drm_i915_private;
 
 #define I915_NUM_ENGINES 8
 
+#define I915_GEM_IDLE_TIMEOUT (HZ / 5)
+
 void i915_gem_park(struct drm_i915_private *i915);
 void i915_gem_unpark(struct drm_i915_private *i915);