hw/pflash_cfi02.c: Mark deliberate fallthrough

Mark the deliberate fallthrough where we treat the case of
an attempt to read flash when it is an unknown command
state as if it were a normal read.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

hw/pflash_cfi02.c

@@ -157,6 +157,7 @@ static uint32_t pflash_read (pflash_t *pfl, hwaddr offset,
         DPRINTF("%s: unknown command state: %x\n", __func__, pfl->cmd);
         pfl->wcycle = 0;
         pfl->cmd = 0;
+        /* fall through to the read code */
     case 0x80:
         /* We accept reads during second unlock sequence... */
     case 0x00: