hwmon: (corsair-cpro) Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a break statement instead of letting the code fall
through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Acked-by: Guenter Roeck <[e-mail]>
Marius Zachmann <[e-mail]>
Signed-off-by: Gustavo A. R. Silva <[e-mail]>

drivers/hwmon/corsair-cpro.c

···
 		default:
 			break;
 		}
+		break;
 	default:
 		break;
 	}