staging:rtl8192u: Rename constants - Style

The constants 'VeryLowRSSI' and 'CTSToSelfTHVal' generate warnings from
checkpatch due to the use of CamelCase naming. The two constants have
been renamed to 'VERY_LOW_RSSI' and 'CTS_TO_SELF_TH_VAL' respectively.

These are coding style changes 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>