staging: wilc1000: remove define DISABLE_PWRSAVE_AND_SCAN_DURING_IP

The driver will use define DISABLE_PWRSAVE_AND_SCAN_DURING_IP always. So remove
the ifdef line and define in Makefile.

Signed-off-by: Glen Lee <glen.lee@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>