staging:rtl8192u: rename SetupTimer > setup_timer - Style

Rename the struct TS_COMMON_INFO member SetupTimer to setup_timer. This
clears the checkpatch issue with CamelCase variable names.

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