drm/exynos: replace drm_detect_hdmi_monitor() with drm_display_info.is_hdmi

Once EDID is parsed, the monitor HDMI support information is available
through drm_display_info.is_hdmi.

This driver calls drm_detect_hdmi_monitor() to receive the same
information, which is less efficient.

Avoid calling drm_detect_hdmi_monitor() and use drm_display_info.is_hdmi
instead.

Signed-off-by: hongao <hongao@uniontech.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>