gstlal_ll_inspiral_event_plotter: update gstlal plot imports

gstlal-inspiral/bin/gstlal_ll_inspiral_event_plotter

@@ -49,8 +49,8 @@ from gstlal import events
 from gstlal import far
 from gstlal import inspiral
 from gstlal import lvalert_helper
-from gstlal import plotfar
-from gstlal import plotpsd
+from gstlal.plots import far as plotfar
+from gstlal.plots import psd as plotpsd
 
 from ligo.lw import utils as ligolw_utils
 from ligo.lw import lsctables