staging: wilc1000: Remove unused function wilc_lock_timeout

Semaphore are going away in the future, so remove the unused function
wilc_lock_timeout which calls a semaphore api but has no users.

Signed-off-by: Binoy Jayan <binoy.jayan@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>