USB: ice40-hcd: Force the chip select to sleep state during resume

The SPI controller driver may not put the chip select in sleep state
at the end of the transaction when there is only one slave connected.
The chip select is put into sleep during runtime suspend.

If the USB bus is runtime resumed before the SPI controller is runtime
suspended, the chip select will be in active state. As the chip select
is overridden temporarily using gpiolib, the chip select state also
needs to be forced to sleep state. Otherwise when the next SPI
transaction is initiated the SPI driver thinks that chip select is
in active state and proceed to the data transfer phase where as the
chip select is not active.

Change-Id: I4908ed7cc849cc849059b5697b6f3e328f42f944
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>