blockgroup_lock.h: remove debris from bgl_lock_ptr() conversion

An obsolete comment and extra parentheses were left over from when the
sb_bgl_lock() macro was replaced with the bgl_lock_ptr() function.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>

include/linux/blockgroup_lock.h

@@ -49,14 +49,10 @@ static inline void bgl_lock_init(struct blockgroup_lock *bgl)
 		spin_lock_init(&bgl->locks[i].lock);
 }
 
-/*
- * The accessor is a macro so we can embed a blockgroup_lock into different
- * superblock types
- */
 static inline spinlock_t *
 bgl_lock_ptr(struct blockgroup_lock *bgl, unsigned int block_group)
 {
-	return &bgl->locks[(block_group) & (NR_BG_LOCKS-1)].lock;
+	return &bgl->locks[block_group & (NR_BG_LOCKS-1)].lock;
 }
 
 #endif