Staging: rtl8723bs: remove useless structs in rtw_security.h

Remove the following unreferenced struct in include/rtw_security.h:

	struct sha256_state

Signed-off-by: Marco Cesati <marcocesati@gmail.com>
Link: https://lore.kernel.org/r/20210322133717.17797-12-marcocesati@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>