drm/i915: Correct typo for __i915_gem_active_get_rcu in a comment

I mistyped and added an extra _request_ to __i915_gem_active_get_rcu()
Also, the same happened to another comment for i915_gem_active_get_rcu()

Reported-by: Mika Kuoppala <[e-mail]>
Signed-off-by: Chris Wilson <[e-mail]>
Reviewed-by: Mika Kuoppala <[e-mail]>
Link: http://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/i915_gem_request.c

···
 	 * We use RCU to look up requests in flight. The lookups may
 	 * race with the request being allocated from the slab freelist.
 	 * That is the request we are writing to here, may be in the process
-	 * of being read by __i915_gem_active_get_request_rcu(). As such,
+	 * of being read by __i915_gem_active_get_rcu(). As such,
 	 * we have to be very careful when overwriting the contents. During
 	 * the RCU lookup, we change chase the request->engine pointer,
 	 * read the request->fence.seqno and increment the reference count.

drivers/gpu/drm/i915/intel_ringbuffer.h

···
 
 	/* An RCU guarded pointer to the last request. No reference is
 	 * held to the request, users must carefully acquire a reference to
-	 * the request using i915_gem_active_get_request_rcu(), or hold the
+	 * the request using i915_gem_active_get_rcu(), or hold the
 	 * struct_mutex.
 	 */
 	struct i915_gem_active last_request;