staging: rtl8192u: r8192U_core.c: Cleaning up variable is set more than once

A struct member variable is set to the same value more than once

This was found using a static code analysis program called cppcheck.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>