SyncPrim/linux-sync-2.md: Fix missed description about spinlock api

Signed-off-by: SeongJae Park <sj38.park@gmail.com>

SyncPrim/linux-sync-2.md

@@ -12,7 +12,7 @@ We saw the [API](https://en.wikipedia.org/wiki/Application_programming_interface
 * `spin_lock` - acquires given `spinlock`;
 * `spin_lock_bh` - disables software [interrupts](https://en.wikipedia.org/wiki/Interrupt) and acquire given `spinlock`.
 * `spin_lock_irqsave` and `spin_lock_irq` - disable interrupts on local processor and preserve/not preserve previous interrupt state in the `flags`;
-* `spin_unlock` - releases given `spinlock`;
+* `spin_unlock` - releases given `spinlock` and acquire given `spinlock`;
 * `spin_unlock_bh` - releases given `spinlock` and enables software interrupts;
 * `spin_is_locked` - returns the state of the given `spinlock`;
 * and etc.