staging: rtl8723bs: remove unused log function

remove unused sd_f0_reg_dump() function.

Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Link: https://lore.kernel.org/r/397a4082fa2a49c67ac7d6869284334d3fa7bea6.1619254603.git.fabioaiuto83@gmail.com


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