lockref: fix docbook argument names

The code got rewritten, but the comments got copied as-is from older
versions, and as a result the argument name in the comment didn't
actually match the code any more.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/lockref.c

@@ -31,7 +31,7 @@
 
 /**
  * lockref_get - Increments reference count unconditionally
- * @lockcnt: pointer to lockref structure
+ * @lockref: pointer to lockref structure
  *
  * This operation is only valid if you already hold a reference
  * to the object, so you know the count cannot be zero.
@@ -52,7 +52,7 @@ EXPORT_SYMBOL(lockref_get);
 
 /**
  * lockref_get_not_zero - Increments count unless the count is 0
- * @lockcnt: pointer to lockref structure
+ * @lockref: pointer to lockref structure
  * Return: 1 if count updated successfully or 0 if count was zero
  */
 int lockref_get_not_zero(struct lockref *lockref)
@@ -80,7 +80,7 @@ EXPORT_SYMBOL(lockref_get_not_zero);
 
 /**
  * lockref_get_or_lock - Increments count unless the count is 0
- * @lockcnt: pointer to lockref structure
+ * @lockref: pointer to lockref structure
  * Return: 1 if count updated successfully or 0 if count was zero
  * and we got the lock instead.
  */
@@ -105,7 +105,7 @@ EXPORT_SYMBOL(lockref_get_or_lock);
 
 /**
  * lockref_put_or_lock - decrements count unless count <= 1 before decrement
- * @lockcnt: pointer to lockref structure
+ * @lockref: pointer to lockref structure
  * Return: 1 if count updated successfully or 0 if count <= 1 and lock taken
  */
 int lockref_put_or_lock(struct lockref *lockref)