mac80211_hwsim: mark expected switch fall-through

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

This patch fixes the following warning:

drivers/net/wireless/mac80211_hwsim.c: In function ‘init_mac80211_hwsim’:
drivers/net/wireless/mac80211_hwsim.c:3853:21: warning: this statement may fall through [-Wimplicit-fallthrough=]

    param.reg_strict = true;
    ~~~~~~~~~~~~~~~~~^~~~~~

drivers/net/wireless/mac80211_hwsim.c:3854:3: note: here
case HWSIM_REGTEST_DRIVER_REG_ALL:
^~~~

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

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

---
 drivers/net/wireless/mac80211_hwsim.c | 1 +
 1 file changed, 1 insertion(+)

index 60ca13e0f15b..b5274d1f30fa 100644
@@ -3851,6 +3851,7 @@ static int __init init_mac80211_hwsim(void)
 			break;
 		case HWSIM_REGTEST_STRICT_ALL:
 			param.reg_strict = true;
+			/* fall through */
 		case HWSIM_REGTEST_DRIVER_REG_ALL:
 			param.reg_alpha2 = hwsim_alpha2s[0];
 			break;

2.21.0