core: set the active state using the request flags

core: set the active state using the request flags

Having to always set the active state in the line request config
structure makes users create unnecessary boilerplate code. Remove the
active state field from the config structure and add a new flag, which
when set, sets the active state to low, while high is the default.

This patch updates the main request function and all the callers - we
still need to update all the helper request routines.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>