staging: rtl8723bs: remove unused code blocks conditioned by never set CONFIG_SIGNAL_DISPLAY_DBM

remove conditional code blocks checked by unused CONFIG_SIGNAL_DISPLAY_DBM

cleaning required in TODO file:

find and remove code blocks guarded by never set CONFIG_FOO defines

Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Link: https://lore.kernel.org/r/abfd2f2fa0425d8e5d8618dd64ef40b4974c71b4.1615801721.git.fabioaiuto83@gmail.com


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