busybox

i2c-tools: fix 'i2cdetect -l'

Calling 'i2cdetect -l' only displays usage and exits. Fix it by
correctly parsing command-line arguments.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>