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

remove conditional code blocks checked by unused
CONFIG_SINGLE_RECV_BUF

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/8e86b8adb1dcec67a7d437a362105bb96f370686.1615907632.git.fabioaiuto83@gmail.com


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