drm/i915/guc: Update name and prototype of i915_guc_log_control

i915_guc_log_control is GuC interface and GuC APIs that are not user
facing should be named with "intel_guc" prefix hence we change name to
intel_guc_log_control. Also changed the parameter to intel_guc struct.

v2: Move log vma check to intel_guc_log_control (Michal)
    Return -ENODEV when log isn't initialized. (Chris)

Suggested-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/1516808821-3638-4-git-send-email-sagar.a.kamble@intel.com
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index d3def0e..3849ded 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2471,10 +2471,7 @@ static int i915_guc_log_control_set(void *data, u64 val)
 	if (!HAS_GUC(dev_priv))
 		return -ENODEV;
 
-	if (!dev_priv->guc.log.vma)
-		return -EINVAL;
-
-	return i915_guc_log_control(dev_priv, val);
+	return intel_guc_log_control(&dev_priv->guc, val);
 }
 
 DEFINE_SIMPLE_ATTRIBUTE(i915_guc_log_control_fops,