get_short_attr_name(): Handle channels with modifiers
get_short_attr_name(): Handle channels with modifiers

For channels with modifiers we need to strip the first three instead of the
first two elements to get the short name.

Signed-off-by: Lars-Peter Clausen <3318dc5ce3e4fb7c28a0b841b6801c884e1d0896@metafoo.de>

sensarliar/libiio,sensarliar/libiio,Sunderfield/libiio,Sunderfield/libiio,analogdevicesinc/libiio,gburca/libiio,analogdevicesinc/libiio,gburca/libiio,Sunderfield/libiio,gburca/libiio,analogdevicesinc/libiio,analogdevicesinc/libiio,sensarliar/libiio