staging:rtl8192u: Remove enum CHNLOP - Style

The enumerated type CHNLOP is only used as a member variable of the
structure RT_HIGH_THROUGHPUT. Whilst this member variable is initialised
it is never actually used in the code. To simplify the code both the
enumerated type and the member variable have been removed.

This is 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>