staging: rtl8723bs: Remove space before tabs

Remove space before tabs to fix checkpatch warning.
Issue found by checkpatch.
Signed-off-by: Javier F. Arias <jarias.linux@gmail.com>
Link: https://lore.kernel.org/r/120800f884986092ca757235781d9ddc740ec832.1570672544.git.jarias.linux@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>