Documentation: locking: mutex-design: fix duplicated word

Change the phrase "at at least" to "to at least" to be more
readable.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200703213649.30948-2-rdunlap@infradead.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/locking/mutex-design.rst

@@ -28,7 +28,7 @@ and implemented in kernel/locking/mutex.c. These locks use an atomic variable
 (->owner) to keep track of the lock state during its lifetime.  Field owner
 actually contains `struct task_struct *` to the current lock owner and it is
 therefore NULL if not currently owned. Since task_struct pointers are aligned
-at at least L1_CACHE_BYTES, low bits (3) are used to store extra state (e.g.,
+to at least L1_CACHE_BYTES, low bits (3) are used to store extra state (e.g.,
 if waiter list is non-empty).  In its most basic form it also includes a
 wait-queue and a spinlock that serializes access to it. Furthermore,
 CONFIG_MUTEX_SPIN_ON_OWNER=y systems use a spinner MCS lock (->osq), described