[Qemu-trivial] [PATCH-for-4.1? 6/7] vl: Rewrite a fall through comment

[Philippe Mathieu-Daudé]

GCC9 is confused by this comment when building with CFLAG
-Wimplicit-fallthrough=2:

  vl.c: In function ‘qemu_ref_timedate’:
  vl.c:773:15: error: this statement may fall through 
[-Werror=implicit-fallthrough=]
    773 |         value -= rtc_realtime_clock_offset;
        |         ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
  vl.c:775:5: note: here
    775 |     case QEMU_CLOCK_VIRTUAL:
        |     ^~~~
  cc1: all warnings being treated as errors

Rewrite the comment using 'fall through' which is recognized by
GCC and static analyzers.

Reported-by: Stefan Weil <address@hidden>
Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
---
 vl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/vl.c b/vl.c
index a5808f9a02..f5cf71e3b4 100644
--- a/vl.c
+++ b/vl.c
@@ -771,7 +771,7 @@ static time_t qemu_ref_timedate(QEMUClockType clock)
     switch (clock) {
     case QEMU_CLOCK_REALTIME:
         value -= rtc_realtime_clock_offset;
-        /* no break */
+        /* fall through */
     case QEMU_CLOCK_VIRTUAL:
         value += rtc_ref_start_datetime;
         break;
-- 
2.20.1