display: Integrate plugin is_lcdon_blocked() into display_is_lcdon_blocked()

display: Integrate plugin is_lcdon_blocked() into display_is_lcdon_blocked()

Those is_lcdon_blocked(), scattered throughout the plugins, has been
gathered into display_is_lcdon_blocked() except the wearable one. The
display_plugin_is_lcd_on_blocked() is removed accordingly.

Change-Id: I3affc0dae9a50bcfb16df1036a5944d41b34c0cf
Signed-off-by: Youngjae Cho <y0.cho@samsung.com>