platform/x86: int3472: add hpd pin support

Typically HDMI to MIPI CSI-2 bridges have a pin to signal image data is
being received. On the host side this is wired to a GPIO for polling or
interrupts. This includes the Lontium HDMI to MIPI CSI-2 bridges
lt6911uxe and lt6911uxc.

The GPIO "hpd" is used already by other HDMI to CSI-2 bridges, use it
here as well.

Signed-off-by: Dongcheng Yan <dongcheng.yan@intel.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Fixes: 20244cba ("media: i2c: change lt6911uxe irq_gpio name to "hpd"")
Cc: stable@vger.kernel.org
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>