staging: rtl8723bs: hal: Remove set but unused variable

Removed set but unused variable. Issue reported by kernel test robot
building with GCC W=1 for PowerPC target architecture.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Link: https://lore.kernel.org/r/20210514090401.16123-3-fmdefrancesco@gmail.com


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