staging: rtl8723bs: hal: Remove three set but unused variables

Removed three set but unused variables. Issue detected by GCC while
building for x86_64.

Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Link: https://lore.kernel.org/r/20210514090401.16123-2-fmdefrancesco@gmail.com


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