staging: wilc1000: rename 'host_interface' source and header

Rename 'host_interface' source and header file to include the 'wilc_'
prefix in its name.

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>