USB: speedtch.c fix sparse shadowed variable warning

i is used only as a for-loop index no need to declare another.
drivers/usb/atm/speedtch.c:832:7: warning: symbol 'i' shadows an earlier one
drivers/usb/atm/speedtch.c:766:6: originally declared here

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>