staging:rtl8192u: Rename cck_Rx_path - Style

Rename the member variable cck_Rx_path to cck_rx_path. This clears
the checkpatch issue with CamelCase naming.

This is a coding style change which should have no impact one runtime
code execution.

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