Refactor: controller: Avoid void pointers in lrm_state_t

This code is only used within the controller, so we don't have to worry
about what's exposed. The value assigned to the conn member is always an
lrmd_t, and the value assigned to the remote_ra_data member is always a
remote_ra_data_t.

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>