staging: wilc1000: Handle_AddBASession: remove unused function

This patch removes unused a function Handle_AddBASession.
And, removes the relation define.

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>