drm: exynos: hdmi: turn off HPD interrupt in HDMI chip

The plug/unplug interrupt are handled by a separate interrupt.
So there is no need to replicate this mechanism in HDMI core.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>