efx: fix serial mode jumpy behavior
efx: fix serial mode jumpy behavior

kripton/qlcplus,mcallegari/qlcplus,plugz/qlcplus,mcallegari/qlcplus,nedmech/qlcplus,nedmech/qlcplus,peternewman/qlcplus,plugz/qlcplus,nedmech/qlcplus,kripton/qlcplus,nedmech/qlcplus,sbenejam/qlcplus,peternewman/qlcplus,mcallegari/qlcplus,nedmech/qlcplus,sbenejam/qlcplus,kripton/qlcplus,peternewman/qlcplus,nedmech/qlcplus,joepadmiraal/qlcplus,joepadmiraal/qlcplus,mcallegari/qlcplus,joepadmiraal/qlcplus,mcallegari/qlcplus,plugz/qlcplus,plugz/qlcplus,sbenejam/qlcplus,sbenejam/qlcplus,plugz/qlcplus,kripton/qlcplus,kripton/qlcplus,peternewman/qlcplus,mcallegari/qlcplus,joepadmiraal/qlcplus,plugz/qlcplus,sbenejam/qlcplus,sbenejam/qlcplus,sbenejam/qlcplus,mcallegari/qlcplus,kripton/qlcplus,peternewman/qlcplus,joepadmiraal/qlcplus,peternewman/qlcplus,joepadmiraal/qlcplus,kripton/qlcplus,plugz/qlcplus