staging: vt6655: Remove unused code inside switch case

This patch removes dead code in private_ioctl function and
iwctl_siwmode function, in file ioctl.c.

Inside switch, for a case no code gets executed
after break.

This was detected by smatch.

Signed-off-by: Tapasweni Pathak <tapaswenipathak@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>