staging: wilc1000: move WILC_MULTICAST_TABLE_SIZE define to wilc_wlan_if.h file

This patch moves WILC_MULTICAST_TABLE_SIZE define to wilc_wlan_if.h file.
This define is used to three files(host_interface.c,host_interface.h,
linux_wlan.c) these files already include wilc_wlan_if.h file in common.

Signed-off-by: Chris Park <chris.park@atmel.com>
Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>