usb: ftdi-elan: remove variable l

Variable l is just being accumulated and it's never used
anywhere else. The variable and the addition are redundant so
remove it.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20221111165724.557152-1-colin.i.king@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>