staging: rtl8723bs: remove undefined function prototypes

remove undefined function prototypes.

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Link: https://lore.kernel.org/r/77c0c9027448be020a00e7ded9ffeb967341b588.1619794331.git.fabioaiuto83@gmail.com


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