Mark switch cases where we are expecting to fall through.
This patch fixes the following warning:
drivers/net/ethernet/toshiba/spider_net.c: In function 'spider_net_release_tx_chain':
drivers/net/ethernet/toshiba/spider_net.c:783:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
    if (!brutal) {
       ^
drivers/net/ethernet/toshiba/spider_net.c:792:3: note: here
   case SPIDER_NET_DESCR_RESPONSE_ERROR:
   ^~~~
Notice that, in this particular case, the code comment is
modified in accordance with what GCC is expecting to find.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
                        /* fallthrough, if we release the descriptors
                         * brutally (then we don't care about
                         * SPIDER_NET_DESCR_CARDOWNED) */
+                       /* Fall through */
 
                case SPIDER_NET_DESCR_RESPONSE_ERROR:
                case SPIDER_NET_DESCR_PROTECTION_ERROR: