OMAPDSS: Panel NEC: Set omap_dss_device states correctly

The display state parameter of omap_dss_device struct is not being set correctly
in the panel driver NEC panel driver panel-nec-nl8048hl11-01b.c. Set the correct
states in the panel's enable/disable/suspend/resume functions.

CC: Erik Gilling <konkers@android.com>
Signed-off-by: Archit Taneja <archit@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>