drm/i915: Fixup kerneldoc for intel_uc_fw_upload()

Just a parameter name change that was lost to kerneldoc.

drivers/gpu/drm/i915/intel_uc_fw.c:209: warning: Function parameter or member 'xfer' not described in 'intel_uc_fw_upload'
drivers/gpu/drm/i915/intel_uc_fw.c:209: warning: Excess function parameter 'loader' description in 'intel_uc_fw_upload'

v2: Add the Returns:
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180214105332.30230-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_uc_fw.c

@@ -197,11 +197,12 @@ void intel_uc_fw_fetch(struct drm_i915_private *dev_priv,
 
 /**
  * intel_uc_fw_upload - load uC firmware using custom loader
- *
  * @uc_fw: uC firmware
- * @loader: custom uC firmware loader function
+ * @xfer: custom uC firmware loader function
  *
  * Loads uC firmware using custom loader and updates internal flags.
+ *
+ * Return: 0 on success, non-zero on failure.
  */
 int intel_uc_fw_upload(struct intel_uc_fw *uc_fw,
 		       int (*xfer)(struct intel_uc_fw *uc_fw,