bcache: Annotate switch fall-through

BugLink: https://bugs.launchpad.net/bugs/1784665

This patch avoids that building with W=1 triggers complaints about
switch fall-throughs.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
(cherry picked from commit 9dfbdec7)
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

drivers/md/bcache/util.c

@@ -31,20 +31,27 @@ int bch_ ## name ## _h(const char *cp, type *res)		\
 	case 'y':						\
 	case 'z':						\
 		u++;						\
+		/* fall through */				\
 	case 'e':						\
 		u++;						\
+		/* fall through */				\
 	case 'p':						\
 		u++;						\
+		/* fall through */				\
 	case 't':						\
 		u++;						\
+		/* fall through */				\
 	case 'g':						\
 		u++;						\
+		/* fall through */				\
 	case 'm':						\
 		u++;						\
+		/* fall through */				\
 	case 'k':						\
 		u++;						\
 		if (e++ == cp)					\
 			return -EINVAL;				\
+		/* fall through */				\
 	case '\n':						\
 	case '\0':						\
 		if (*e == '\n')					\