staging:rtl8192u: Remove unused constants - Style

Remove defined constants from code, since they are never actually
used in code. This is a simple coding style change which should have
no impact on runtime code execution.

Signed-off-by: John Whitmore <johnfwhitmore@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>