staging: rtl8712: r8712_wdg_timeout_handler: Remove function

Remove function _r8712_wdg_timeout_handler as all it does is call
r8712_wdg_wk_cmd. Modify call site of _r8712_wdg_timeout_handler to call
r8712_wdg_wk_cmd instead.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>