[PATCH][next] ring-buffer: Fix fall-through warning for Clang

["Gustavo A. R. Silva" <gustavoars@kernel.org>]

In preparation to enable -Wimplicit-fallthrough for Clang, fix
a fall-through warning by replacing a /* fall through */ comment
with the new pseudo-keyword macro fallthrough;

Notice that Clang doesn't recognize /* fall through */ comments as
implicit fall-through markings, so in order to globally enable
-Wimplicit-fallthrough for Clang, these comments need to be
replaced with fallthrough; in the whole codebase.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
JFYI: We had thousands of these sorts of warnings and now we are down
      to just 25 in linux-next. This is one of those last remaining
      warnings.

 kernel/trace/ring_buffer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2c0ee6484990..d1463eac11a3 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3391,7 +3391,7 @@ static void check_buffer(struct ring_buffer_per_cpu *cpu_buffer,
 		case RINGBUF_TYPE_PADDING:
 			if (event->time_delta == 1)
 				break;
-			/* fall through */
+			fallthrough;
 		case RINGBUF_TYPE_DATA:
 			ts += event->time_delta;
 			break;
-- 
2.27.0