[PATCH] watchdog: machzwd: Mark expected switch fall-through

["Gustavo A. R. Silva" <gustavo@embeddedor.com>]

In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warnings:

drivers/watchdog/machzwd.c: In function ‘zf_set_timer’:
./arch/x86/include/asm/io.h:355:14: warning: this statement may fall through [-Wimplicit-fallthrough=]
 #define outw outw
drivers/watchdog/machzwd.c:80:53: note: in expansion of macro ‘outw’
 #define zf_writew(port, data)  { outb(port, INDEX); outw(data, DATA_W); }
                                                     ^~~~
drivers/watchdog/machzwd.c:179:3: note: in expansion of macro ‘zf_writew’
   zf_writew(COUNTER_1, new);
   ^~~~~~~~~
drivers/watchdog/machzwd.c:180:2: note: here
  case WD2:
  ^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/watchdog/machzwd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/watchdog/machzwd.c b/drivers/watchdog/machzwd.c
index 88d823d87a4b..108928dbc754 100644
--- a/drivers/watchdog/machzwd.c
+++ b/drivers/watchdog/machzwd.c
@@ -177,6 +177,7 @@ static inline void zf_set_timer(unsigned short new, unsigned char n)
 	switch (n) {
 	case WD1:
 		zf_writew(COUNTER_1, new);
+		/* fall through */
 	case WD2:
 		zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
 	default:
-- 
2.21.0