drm/i915: Fix documentation for __intel_wait_for_register_fw*

Use section name "Return" and proper error code -ETIMEDOUT
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190802124739.12548-1-michal.wajdeczko@intel.com

drivers/gpu/drm/i915/intel_uncore.c

@@ -1860,7 +1860,7 @@ int i915_reg_read_ioctl(struct drm_device *dev,
  * wish to wait without holding forcewake for the duration (i.e. you expect
  * the wait to be slow).
  *
- * Returns 0 if the register matches the desired condition, or -ETIMEOUT.
+ * Return: 0 if the register matches the desired condition, or -ETIMEDOUT.
  */
 int __intel_wait_for_register_fw(struct intel_uncore *uncore,
 				 i915_reg_t reg,
@@ -1908,7 +1908,7 @@ int __intel_wait_for_register_fw(struct intel_uncore *uncore,
  *
  * Otherwise, the wait will timeout after @timeout_ms milliseconds.
  *
- * Returns 0 if the register matches the desired condition, or -ETIMEOUT.
+ * Return: 0 if the register matches the desired condition, or -ETIMEDOUT.
  */
 int __intel_wait_for_register(struct intel_uncore *uncore,
 			      i915_reg_t reg,