staging: wilc1000: remove manual sleep mode

manual sleep mode was used to put the wilc1000 chip in sleep while in
disconnected state. This is taken care of in the firmware

Signed-off-by: Adham Abozaeid <adham.abozaeid@microchip.com>
Link: https://lore.kernel.org/r/20190725213125.2810-7-adham.abozaeid@microchip.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>