staging: rtl8723bs: remove unused _DBG_871X_LEVEL macro

remove unused _DBG_871X_LEVEL macro,
after DBG_871X_SEL deletion.

Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Link: https://lore.kernel.org/r/83ff6acd438ad2107a9a1c9446cabb22a6c77f0a.1619254603.git.fabioaiuto83@gmail.com


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