drm/exynos: fimd: modify I80 i/f irq relevant routine

For the I80 interface, the video interrupt pending register(VIDINTCON1)
should be handled in fimd_irq_handler() and the video interrupt control
register(VIDINTCON0) should be handled in fimd_enable_vblank() and
fimd_disable_vblank() like RGB interface.
So this patch moves each set / unset routines into proper positions.

Signed-off-by: YoungJun Cho <yj44.cho@samsung.com>
Acked-by: Inki Dae <inki.dae@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>