staging: wilc1000: rename Enable_TCP_ACK_Filter function

This patch rename the Enable_TCP_ACK_Filter function to enable_tcp_ack_filter
to avoid CamelCase naming convention.

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