staging:rtl8192u: Rename octet_string members - Style

Rename the structure octet_string's member variables Octet to octet and
Length to length. This change clears the checkpatch issue with CamelCase
naming of variables.

This is purely a 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>