staging: wilc1000: use proper namespace for macros in wilc_wlan_if.h header

Rename the macros defined in wilc_wlan_if.h header to have clear
namespace. As convention used 'WILC_FW_' prefix for constants defined for
firmware and 'WILC_' prefix for driver constants.

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