staging: rtl8723bs: hal: Remove set but unused variables

staging: rtl8723bs: hal: Remove set but unused variables

Removed set but unused variables. Issue detected by GCC running with
the warning option -Wunused-but-set-variable. Removed the storage of
the values returned but left the reads because it is possible
that removing them can prevent the hardware from working properly.

Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Link: https://lore.kernel.org/r/20210523174547.20646-1-fmdefrancesco@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>