staging: most: core: add comments to mutex and spinlock definitions

This patch adds a comment to the start_mutex and fifo_lock fields of
the most_channel structure definition.
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Link: https://lore.kernel.org/r/1573566036-2279-1-git-send-email-christian.gromm@microchip.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/most/core.c

@@ -52,7 +52,7 @@ struct most_channel {
 	u16 channel_id;
 	char name[STRING_SIZE];
 	bool is_poisoned;
-	struct mutex start_mutex;
+	struct mutex start_mutex; /* channel activation synchronization */
 	struct mutex nq_mutex; /* nq thread synchronization */
 	int is_starving;
 	struct most_interface *iface;
@@ -60,7 +60,7 @@ struct most_channel {
 	bool keep_mbo;
 	bool enqueue_halt;
 	struct list_head fifo;
-	spinlock_t fifo_lock;
+	spinlock_t fifo_lock; /* fifo access synchronization */
 	struct list_head halt_fifo;
 	struct list_head list;
 	struct pipe pipe0;