platform: goldfish: pipe: Update the comment for GFP_ATOMIC

Provide an explanation why GFP_ATOMIC is needed to prevent changing it to
other values.
Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/platform/goldfish/goldfish_pipe.c

@@ -640,7 +640,10 @@ static int get_free_pipe_id_locked(struct goldfish_pipe_dev *dev)
 			return id;
 
 	{
-		/* Reallocate the array */
+		/* Reallocate the array.
+		 * Since get_free_pipe_id_locked runs with interrupts disabled,
+		 * we don't want to make calls that could lead to sleep.
+		 */
 		u32 new_capacity = 2 * dev->pipes_capacity;
 		struct goldfish_pipe **pipes =
 			kcalloc(new_capacity, sizeof(*pipes), GFP_ATOMIC);