staging: wilc1000: host_interface.c : remove unused functions

This patch removes unused functions from the host_interface.c(h).
 - Switch_Log_Terminal
 - Handle_DelBASession
 - host_int_addBASession

This patch includes the removal of the comment for host_int_addBASession
as well.

Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Tony Cho <tony.cho@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>